Predicting Simultaneous Blockade
of Viral Entry and Replication Pathways by Digital Twin v3.1: Validation of the
DTIS and SVEI Indices for the Allicin/Al12N12 Nanocomplex
Jefferson
Lorençoni de Morais1,2*, Heliel Gabriel Borges de Sena3, Larissa
Neres Barbosa3 ,
Lanna Araújo Gomes3
1* Polytechnic School of the Alves
Faria University Center — UNIALFA, Goiânia, Brazil.
2* American Global Technology University – AGTU,
Orlando, EUA.
3 Institute of Phamaceutical and Exact Sciences – UNIGOIÁS,
Goiás, Brazil.
*Correspondence: Jefferson.morais@unialfa.com.br;
DOI: https://doi.org/10.71431/IJRPAS.2026.5607
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Article
Information
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Abstract
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Research Article
Received: 08/06/2026
Accepted:
20/06/2026
Published:30/06/2026
Keywords
Allicin; Digital Twin; SARS-CoV-2;
Al₁₂N₁₂; Molecular Dynamics.
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Extending
the Digital Twin v3.0 published by Morais et al. (IJRPAS, May/2026), this
work presents Digital Twin v3.1 — a seven-layer computational framework that
expands the Mpro (6LU7) inhibition model into a dual-target paradigm,
simultaneously incorporating the S/ACE2 protein (PDB: 6M17) as the second
antiviral target of SARS-CoV-2. Layer 6 integrates real CHARMm36 molecular
dynamics (MD) data from Li & Cheng (2023) for the alliin–6M17 and
allicin–6M17 complexes: neither equilibrates over 100 conformations (in
contrast to 6LU7, where alliin equilibrates at ~50 conformations); the mean
RMSF in the 17-residue S/ACE2 interface active pocket is 0.857 Å (alliin) and
1.128 Å (allicin), a difference of 0.271 Å (24.9%). Layer 7 introduces three
novel metrics: DTIS (Dual-Target Inhibition Score), DTAUC and SVEI
(SARS-CoV-2 Viral Entry Inhibition). The Allicin/Al₁₂N₁₂ complex achieves
NEFI_dual = 14.8×, DTAUC = 42.03 days·inhib. (vs. 2.84 for free allicin),
Peak DTIS = 70.1%, and EDc = −8.10 kcal/mol for S/ACE2 — a more negative
binding energy than for Mpro itself (−6.74 kcal/mol). The ACE2/Mpro ratio =
1.20 indicates structural preference of the nanocomplex for the S/ACE2
interface, suggesting that the primary mechanism of action of Allicin/Al₁₂N₁₂
may be viral entry blockade. The Digital Twin-predicted RMSF for
Allicin/Al₁₂N₁₂ at the S/ACE2 interface is 0.169 Å — a 6.66-fold reduction
below free allicin. The framework remains adaptive: new experimental data (in
vitro stability, real GROMACS MD, ADMET) can recalibrate the model within
minutes.
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INTRODUCTION
Background and Motivation
Allicin (diallyl thiosulfinate,
C₆H₁₀OS₂; CAS 539-86-6) is the principal bioactive compound of Allium sativum
(garlic), with extensively documented anticancer, anti-inflammatory, antiviral,
and antibacterial activities [1,2]. Its principal pharmacological limitation
is rapid degradation in aqueous media (t½ ≈ 3.5–4 days at 37°C, pH 7.4), which
severely restricts therapeutic bioavailability [3,4]. In response to this limitation,
the series of studies published by our group has progressively developed a
multi-scale Digital Twin (DT) framework to model and overcome this instability
through nanocomplexes with Al₁₂N₁₂, B₁₂N₁₂, and C₂₄.
Digital Twin v2.0 (Morais et al., IJRPAS, April/2026) [5] presented the first three-layer
framework for modeling allicin aqueous degradation, parametrized by DFT data
from Mozafari et al. (2025) [6], achieving a Nanocage Protection
Factor (NPF) of 5,498,905× for the Al₁₂N₁₂ complex — representing an extension
of the half-life from 3.6 days to more than 9,999 days. Version 3.0 (Morais et
al., IJRPAS, May/2026) [7] expanded the framework to five
layers, integrating real CHARMm36 MD data from Li & Cheng (2023) [8] for the Mpro target (6LU7) and
introducing the NEFI (14.0×) and SBIS (320.7) metrics. The present work —
Digital Twin v3.1 — completes the dual-target vision explicitly identified in
v3.0 as the next step: simultaneously modeling Mpro inhibition and S/ACE2
interface blockade (6M17), integrating the MD data available in Li & Cheng [8] for both targets.
Importance
of the S/ACE2 Target and the Dual-Target Approach
The SARS-CoV-2 Spike protein (S)
mediates viral entry into host cells by binding to the human ACE2 receptor.
Blocking this interface (PDB: 6M17, resolution 2.90 Å [9]) represents a complementary
antiviral mechanism distinct from Mpro inhibition: while Mpro inhibits
replication in already-infected cells, S/ACE2 blockade prevents infection of
new cells. A compound acting simultaneously on both targets therefore operates at
two distinct points of the viral cycle, reducing the likelihood of resistance
and potentiating the therapeutic effect synergistically [10,11]. Li & Cheng (2023) [8] demonstrated that both alliin and
allicin bind the 6M17 active pocket, with alliin exhibiting a LibDock score of
124.1 (vs. 103.2 for allicin) and forming three hydrogen bonds (ASP499, TRP165,
LYS481) in addition to multiple salt bridges — a consistently more stable
binding profile than allicin.
Vieira et al. (2023) [12] developed VisualDynamics, a web
platform that automates GROMACS simulations via a graphical interface,
demonstrating that the computational barrier for MD is progressively being
democratized. In this context, Digital Twin v3.1 is positioned as a
computationally accessible framework that simulates dual-target pharmacodynamic
behavior without requiring dedicated GPU resources, while maintaining full
traceability and recalibrability.
Objectives
This study aims to: (i) integrate
real CHARMm36 MD data from Li & Cheng (2023) for 6M17 as Layer 6 of the
Digital Twin; (ii) develop Layer 7 — a dual-target pharmacodynamic model
yielding the DTIS, DTAUC, and SVEI metrics; (iii) quantify NEFI_dual and
compare nanocomplex binding affinity for Mpro (6LU7) vs. S/ACE2 (6M17); (iv)
predict the active-pocket RMSF for the Allicin/Al₁₂N₁₂ complex at the 6M17
interface; and (v) identify the central scientific question motivating the next
study in the series.
MATERIALS AND METHODS
Digital Twin v3.1 Architecture
Digital Twin v3.1 fully inherits all layers of
v3.0 [7] and introduces two new ones, as
summarized in Table 1. Implementation was carried out in Python 3.12 (NumPy
1.26, SciPy 1.13, scikit-learn 1.4) with fixed seeds for reproducibility
(numpy.random.seed(42)).
Table 1. Seven-layer architecture of Digital Twin v3.1.
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Layer
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Name
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Data Source
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Primary Output
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1
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Thermodynamic
ODE Engine
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DFT: Mozafari et al. 2025 [6]
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Degradation
kinetics, NPF, t½
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2
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GP MD
Surrogate
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Synthetic physics-based grid
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RMSD, Rg,
SASA, B-factor trajectories
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3
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Experimental
Validation
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Miron 2000; Lawson 2005; Block 1992
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R²=0.9997;
MAPE=10.3%; IR <1.18%
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4
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Real MD —
6LU7 (v3.0)
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Li & Cheng 2023 [8] — CHARMm36
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RMSD/RMSF
anchor for Mpro active pocket
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5
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Mpro
Binding Dynamics (v3.0)
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Layers 1–4 + Hill–Langmuir
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NEFI,
SBIS, inhibition AUC
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6 (NEW)
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Real MD —
6M17 (v3.1)
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Li & Cheng 2023 [8] — CHARMm36
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RMSD/RMSF
anchor for S/ACE2 active pocket; 17 interface residues
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7 (NEW)
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Dual-Target
Model (v3.1)
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Layers 1–6; synergistic model
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DTIS,
DTAUC, SVEI, NEFI_dual
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Layer 6 — Integration of Real MD
Data for 6M17
Li & Cheng (2023) [8] performed molecular docking (DS
LibDock) followed by MD simulation (Discovery Studio 2019, CHARMm36 force
field, explicit solvent) for the alliin–6M17 and allicin–6M17 complexes. The
simulation protocol comprised five stages: Minimization 1, Minimization 2,
Heating, Equilibration, and Production (100 conformations in the RMSD output).
RMSD and RMSF trajectories were digitized from Figures 7 and 8 of Li &
Cheng (2023) and encoded as calibration targets in Digital Twin v3.1.
Key structural features extracted from Li & Cheng data for 6M17 and
incorporated as calibration anchors:
•
Alliin–6M17:
RMSD in continuous fluctuation (2.2–3.6 nm); three hydrogen bonds (ASP499,
TRP165, LYS481); multiple salt bridges (ARG169, LYS481, TRP271, PHE452,
TRP477); van der Waals forces with TRP271.
•
Allicin–6M17:
RMSD in continuous and wider fluctuation; only one hydrogen bond (ARG169) and
one salt bridge (TRP477 via sulfur); hydrophobic interactions with TRP165,
ALA264, TRP271, PHE452, LEU456, LEU503.
•
Neither
complex equilibrates over 100 conformations — a fundamental contrast with 6LU7,
where alliin equilibrates after ~50 conformations.
•
Stable
region: residues 0–600; unstable region: 600–750 (protein larger than 6LU7,
~750 residues).
•
Mean
RMSF of active pocket (17 residues): alliin = 0.857 Å; allicin = 1.128 Å; Δ =
0.271 Å (alliin 24.9% more stable).
Layer
7 — Dual-Target Pharmacodynamic Model
Dual-Target
Inhibition Score (DTIS)
The DTIS quantifies simultaneous inhibition of both targets as a
function of time:
where w_Mpro = 0.55
(weight of replication inhibition), w_ACE2 = 0.45 (weight of entry blockade),
and γ = 0.30 (synergy coefficient, representing the superadditive cooperative
effect of simultaneously blocking both viral mechanisms). The synergy factor is
biologically grounded in viral clearance models demonstrating that the
combination of entry blockade and replication inhibition is superadditive [10].
NEFI_dual —
Nanocage Enhancement Factor for Inhibition (Dual-Target)
NEFI_dual quantifies the dual-target therapeutic sustainability
advantage conferred by nanocage encapsulation, combining binding affinity for
both targets and half-life extension in a single metric.
SVEI — SARS-CoV-2 Viral Entry Inhibition Index
The SVEI represents the S/ACE2 blockade fraction over time,
isolating the viral entry contribution to total inhibition:
This index is particularly
relevant as a preventive metric — high SVEI indicates efficacy in preventing
infection of new cells.
Docking
Data for 6M17 — Nanocomplexes
Binding energies EDc for free allicin and alliin at 6M17
were derived from Li & Cheng (2023) [8] LibDock scores by equivalent
conversion. EDc values for nanocomplexes (Allicin/C₂₄, B₁₂N₁₂, and Al₁₂N₁₂)
against 6M17 were estimated by applying the improvement factors observed at
6LU7 (Mozafari et al. [6]) with a conservative 78% correction
for the larger S/ACE2 pocket (distinct geometry and hydrophobicity). The RMSF
prediction for Allicin/Al₁₂N₁₂ at the 6M17 active pocket used the same B-factor
reduction factor from the v2.0 surrogate (44-fold → RMSF factor 6.66×) applied
to the allicin–6M17 reference value.
RESULTS
AND DISCUSSION
Layer 6 —
Integration of Real MD Data for 6M17
RMSD Analysis
Figure 2 presents the RMSD trajectories for both targets. The behavior
of 6M17 is fundamentally distinct from 6LU7: neither complex (alliin or
allicin) equilibrates over 100 conformations. The physical reason is direct:
6M17 is an S/ACE2 dimer with ~750 residues, substantially larger than the
monomeric Mpro (~306 residues), resulting in an RMSD fluctuation window of
2.2–3.6 nm — more than twice the values observed at 6LU7. Nonetheless,
alliin–6M17 maintains consistently lower fluctuation than allicin–6M17,
reflecting its denser interaction network (3 H-bonds + 3 salt bridges) versus
allicin's single hydrogen bond.
This observation carries an important implication for the Digital Twin:
while for 6LU7 the v2.0 GP surrogate predicts rapid equilibration for Al₁₂N₁₂
(justified by high |Ead| = 40.28 kcal/mol), for 6M17 the equilibration
prediction will be slower — expected given that the S/ACE2 interface pocket is
topologically more open and the larger protein distributes thermal fluctuations
across more residues.
Figure 2. (a) RMSD trajectories for
alliin–6LU7 and allicin–6LU7. Alliin equilibrates at ~1.10 nm after conformation
50; allicin in continuous fluctuation. (b) RMSD trajectories for alliin–6M17
and allicin–6M17: neither equilibrates (6M17 is a dimer, ~750 residues). Data:
Li & Cheng (2023) [8], CHARMm36, Discovery Studio.
RMSF Analysis — 6M17 Active Pocket
Figure 3 compares RMSF at the active pockets of 6LU7 (12 residues) and
6M17 (17 residues). For 6M17, the residues with the largest alliin–allicin
differential are: TRP477 (Δ = 0.35 Å) and PHE452 (Δ = 0.33 Å) — which compose
the deep hydrophobic cavity of the S/ACE2 interface. Notably, the mean pocket
RMSF for 6M17 for allicin (1.128 Å) is 3.7% larger than for 6LU7 (1.088 Å),
consistent with the greater flexibility of the S/ACE2 interface compared to the
compact Mpro catalytic pocket.
The Digital Twin prediction for Allicin/Al₁₂N₁₂ at the 6M17 pocket is
0.169 Å — virtually identical to the 6LU7 prediction (0.163 Å), since both
derive from the same B-factor reduction factor (6.66×). This is physically
coherent: the stabilizing effect of the Al₁₂N₁₂ nanocage on allicin is
independent of the protein target — it is a property of the ligand–nanocage
complex itself.
Figure 3. (a) RMSF per residue in the 6LU7
active pocket (12 residues). (b) RMSF per residue in the 6M17 active pocket (17
residues). Orange bars = alliin; red = allicin; purple = Digital Twin
prediction for Allicin/Al₁₂N₁₂ (6.66× reduction). MD data: Li & Cheng 2023 [8].
Table 2. S/ACE2 active pocket RMSF (6M17) - Comparative summary.
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Residue
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Index
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Alliin (Å)
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Allicin (Å)
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ΔAllicin−Alliin (Å)
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Al₁₂N₁₂ pred. (Å)
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TRP165
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165
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0.92
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1.18
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0.26
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0.177
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ARG169
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169
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0.88
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1.14
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0.26
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0.171
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TRP271
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271
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0.91
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1.20
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0.29
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0.180
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PHE452
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452
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0.95
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1.28
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0.33
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0.192
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TRP477
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477
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0.97
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1.32
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0.35*
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0.198
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LYS481
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481
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0.85
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1.12
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0.27
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0.168
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ASP499
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499
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0.80
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1.08
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0.28
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0.162
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VAL506
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506
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0.83
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1.10
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0.27
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0.165
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Mean (17 res.)
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—
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0.857
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1.128
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0.271 (24.9%↑)
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0.169
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* TRP477: largest alliin–allicin differential in the S/ACE2
pocket. Al₁₂N₁₂ prediction: 6.66× reduction factor (derived from v2.0 surrogate
B-factor). MD data: Li & Cheng 2023 [8].
Layer 7 —
Dual-Target Model Results
NEFI_dual and
DTAUC
Table 3 and Figure 4 present the complete Layer 7 results. The
Allicin/Al₁₂N₁₂ complex achieves NEFI_dual = 14.8× and DTAUC = 42.03
inhibition-days, representing 14.8 times more sustained dual-target inhibition
than free allicin over 60 days. This result marginally exceeds the
single-target NEFI (Mpro only) of 14.0× reported in v3.0 [7], owing to the added S/ACE2
component: the high affinity EDc = −8.10 kcal/mol for 6M17 elevates the Peak
DTIS from 53.1% (free allicin) to 70.1% (Al₁₂N₁₂), contributing the synergy
fraction.
An unexpected result of high theoretical relevance is the ACE2/Mpro
ratio pattern. For all analyzed complexes, binding affinity for the S/ACE2
target exceeds that for Mpro (ratio > 1.0). For Allicin/Al₁₂N₁₂, this ratio
is 1.20, indicating that the nanocomplex has a structural preference for the
S/ACE2 interface. This suggests that the primary mechanism of action of
Allicin/Al₁₂N₁₂ may be viral entry blockade — a hypothesis with clinically
relevant implications, since a preventive agent (entry blockade) has a distinct
prophylactic application from a therapeutic agent (replication inhibition).
Table 3. Layer 7 — Complete dual-target
metrics for all nanocomplexes (T = 37°C, pH 7.4, 60 days).
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Species
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DTAUC
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NEFI_dual (×)
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Mpro AUC
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ACE2 AUC
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Peak DTIS (%)
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EDc ACE2 (kcal/mol)
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Free
Allicin
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2.84
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1.0
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2.46
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2.89
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53.1
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−5.15
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Allicin/C₂₄
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18.82
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6.6
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16.39
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17.92
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64.1
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−6.82
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Allicin/B₁₂N₁₂
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27.24
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9.6
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21.49
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27.67
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45.4
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−4.28
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Allicin/Al₁₂N₁₂
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42.03
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14.8
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34.45
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37.10
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70.1
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−8.10
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DTAUC = area under the DTIS curve (inhibition-days, 0–60
days); NEFI_dual = DTAUC(species)/DTAUC(free allicin); Peak DTIS = maximum
value at t = 0 (%); EDc ACE2 derived from Li & Cheng 2023 [8] with scaling
from Mozafari 2025 [6].
Figure 4. (a) Dual-Target Inhibition Score
(DTIS, %) curves over 60 days for the four complexes. Allicin/Al₁₂N₁₂ and
B₁₂N₁₂ maintain essentially constant inhibition; free allicin decays to zero in
~20 days. (b) NEFI_dual per species — Al₁₂N₁₂ achieves 14.8× superiority over
free allicin.
AUC
Comparison by Target and Binding Energies
Figure 5 contrasts inhibition AUCs for Mpro versus S/ACE2 and the EDc
binding energies. Consistently, all complexes show AUC_ACE2 > AUC_Mpro —
except Allicin/C₂₄ — reflecting that S/ACE2 target affinity is systematically
higher. This observation is coherent with the interaction scale reported by Li
& Cheng [8] for 6M17: the S/ACE2 interface
pocket is topologically more open and accommodates more extensive polar and
hydrophobic interactions than the compact Mpro catalytic pocket.
Figure 5. (a) Sustained inhibition AUC: solid bars = Mpro (6LU7);
hatched bars = S/ACE2 (6M17). For Al₁₂N₁₂, AUC_ACE2 (37.10) > AUC_Mpro
(34.45). (b) Binding energies EDc per target: Al₁₂N₁₂ achieves −8.10 kcal/mol
at S/ACE2, exceeding its own Mpro value (−6.74 kcal/mol). ACE2/Mpro ratio =
1.20.
SVEI — Viral
Entry Inhibition and Multi-Metric Superiority
Figure 6(a) shows the SVEI curves over time. Allicin/Al₁₂N₁₂ maintains a
maximum blockade of ~62% over the S/ACE2 interface essentially constantly for
60 days, while free allicin decays to negligible blockade in ~25 days. Panel
(b) synthesizes the multi-metric superiority of Al₁₂N₁₂ relative to free
allicin: 14.8× in NEFI_dual, 14.8× in DTAUC, 15.2× in Mpro AUC, and 12.8× in
ACE2 AUC.
The most robust result of Layer 7 is that Allicin/Al₁₂N₁₂ dominates
across all pharmacodynamic metrics — single-target (NEFI = 14.0× from v3.0 [7]) and dual-target (NEFI_dual = 14.8×
from this work). The margin of superiority over Allicin/B₁₂N₁₂ (NEFI_dual =
9.6×) is amplified by the fact that Al₁₂N₁₂ combines the highest binding
affinity with the highest thermodynamic stability. Allicin/C₂₄, despite its
intermediate affinity, presents NEFI_dual of only 6.6× owing to its modest
kinetic protection (NPF = 7.0×).
Figure 6. (a) SVEI — Viral Entry Inhibition (S/ACE2 blockade, %)
over 60 days. Al₁₂N₁₂ maintains ~62% entry blockade constantly. (b)
Multi-metric superiority: all metrics normalized to Free Allicin = 1.0×.
Al₁₂N₁₂ exceeds free allicin by 14.8× in DTAUC and 14.8× in NEFI_dual.
Figure 1. (a) ODE aqueous degradation kinetics for free allicin and
nanocomplexes at T = 37°C, pH 7.4. Dotted vertical lines indicate half-life
points for free allicin (3.6 days) and Allicin/C₂₄ (25 days); B₁₂N₁₂ and
Al₁₂N₁₂ complexes are effectively stable throughout. (b) Nanocage Protection
Factor (NPF) on log₁₀ scale — Al₁₂N₁₂ achieves NPF = 5,498,905×. Layer 1
calibrated Ea = 17.75 kcal/mol.
Contextualization with Literature
Li & Cheng (2023) [8] concluded that alliin exhibits
stronger binding than allicin at both targets (6LU7 and 6M17), with LibDock
scores of 124.1 vs. 98.7 for Mpro and 124.1 vs. 103.2 for S/ACE2. The present
work contextualizes this finding: although alliin is a superior ligand, allicin
encapsulated in Al₁₂N₁₂ achieves EDc = −8.10 kcal/mol at S/ACE2 — surpassing
the estimated equivalent for alliin (−6.10 kcal/mol) — while delivering
sustained temporal exposure that neither free compound can provide. This is the
second consecutive case in the series where Al₁₂N₁₂ nanocomplexation reverses
the potency hierarchy, converting a moderately potent, kinetically unstable
natural compound into a candidate with pharmaceutical-grade stability and
superior affinity.
Vieira et al. (2023) [12] demonstrated that MD simulations via
GROMACS can be performed by non-specialist users through the VisualDynamics
platform. This methodological democratization is directly relevant to the next
step in this series: real MD for the Allicin/Al₁₂N₁₂ and Allicin/B₁₂N₁₂
nanocomplexes could be executed via VisualDynamics without dedicated HPC
infrastructure, making GP surrogate experimental validation accessible. Digital
Twin v3.1 provides exactly the data needed to configure these simulations:
initial structures (Ead, geometric parameters), temperature and pH conditions,
and quantitative predictions of RMSD, Rg, SASA, and B-factor to be validated or
refuted.
LIMITATIONS AND FUTURE DIRECTIONS
Limitations of the Present Work
EDc values for nanocomplexes at 6M17 are estimates based on conservative
scaling of the Mozafari et al. [6] results for 6LU7, not on direct
molecular docking against the 6M17 structure. The binding hierarchy (Al₁₂N₁₂
> C₂₄ > free allicin > B₁₂N₁₂) is consistent across targets, but
absolute values for 6M17 should be treated as first approximations.
Additionally, the synergy coefficient γ = 0.30 in the DTIS is physically
motivated but not calibrated against experimental dual-target viral clearance
data.
Critical Next Step: Direct Docking
against 6M17
The natural next computational step in this series is direct molecular
docking of the Al₁₂N₁₂, B₁₂N₁₂, and C₂₄ nanocomplexes against the 6M17
structure (PDB: 6M17, resolution 2.90 Å) using AutoDock Vina or Glide, providing
EDc values calibrated directly for S/ACE2. This would replace the Layer 6
estimates with computed values and allow Layer 7 recalibration with
experimental precision.
Real GROMACS MD for the
Nanocomplexes
The GP surrogate must ultimately be retrained against real GROMACS
all-atom MD trajectories for Allicin/Al₁₂N₁₂ — prioritarily for 6LU7, then
6M17. The VisualDynamics platform [12] represents an accessible route for
executing these simulations without dedicated HPC infrastructure. The Digital
Twin quantitative predictions (RMSD_eq = 0.485 Å, RMSF = 0.163–0.169 Å, SASA =
6.96 nm²) are the primary hypotheses to be validated or refuted at this stage.
In Vitro Stability Assays
The NPF = 5,498,905× for Al₁₂N₁₂ is a thermodynamic upper bound derived
from DFT ΔG. UV-Vis kinetic degradation assays (242 nm) of the Allicin/Al₁₂N₁₂
complex in aqueous solution (37°C, pH 7.4) represent the most urgent and direct
experimental validation in the entire series.
Extension to Alliin Nanocomplexes
Given alliin's demonstrated superior binding to both targets (Li &
Cheng [8]), DFT characterization of alliin/Al₁₂N₁₂, alliin/B₁₂N₁₂,
and alliin/C₂₄ would complete the candidate space and potentially reveal
NEFI_dual values even higher than those reported here for allicin.
CONCLUSION
Digital Twin v3.1 presents, for the first time
in the literature, a seven-layer computational framework for modeling the
simultaneous dual-target inhibition of SARS-CoV-2 Mpro (6LU7) and S/ACE2 (6M17)
by nanocage-encapsulated allicin complexes. Integration of real CHARMm36 MD
data from Li & Cheng (2023) for 6M17 (Layer 6) revealed that neither
alliin–6M17 nor allicin–6M17 complexes equilibrate over 100 conformations —
behavior contrasting with 6LU7, where alliin equilibrates. The mean RMSF of the
17-residue S/ACE2 interface active pocket is 24.9% larger for allicin (1.128 Å)
than for alliin (0.857 Å), with TRP477 exhibiting the largest differential (Δ =
0.35 Å).
Layer 7 introduces three novel metrics — DTIS, DTAUC, and SVEI — that
quantify sustained dual-target inhibition. The Allicin/Al₁₂N₁₂ complex
dominates all indicators: NEFI_dual = 14.8×, DTAUC = 42.03 inhibition-days (vs.
2.84 for free allicin), Peak DTIS = 70.1%, and EDc_ACE2 = −8.10 kcal/mol — the
most negative binding energy among all candidates at any target. The
EDc_ACE2/EDc_Mpro ratio of 1.20 suggests structural preference of the
nanocomplex for the S/ACE2 interface, positioning Al₁₂N₁₂ potentially as a
preventive agent (entry blockade) in addition to a therapeutic one (replication
inhibition).
Digital Twin v3.1 closes the dual-target gap explicitly identified in
v3.0, while opening the next critical question: are the estimated docking
values for nanocomplexes at 6M17 confirmed by direct calculation? The answer,
via AutoDock Vina/Glide against the 6M17 structure, is the objective of the
next study in this series.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
ACKNOWLEDGEMENTS
The authors thank the Polytechnic School of UNIALFA and the Institute of
Pharmaceutical Sciences of UNIGOIAS for institutional support. This study was
conducted entirely with open-source and no-cost computational resources,
consistent with the Digital Twin framework's design for accessibility. The
authors acknowledge the MD work of Li & Cheng (ISAIMS 2023) and the DFT
work of Mozafari, Baei, and Tazikeh Lemeski (Sci. Rep. 2025), fundamental to
this series of studies.
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