Phytochemical Profile, In Vitro Bioactivity Evaluation, In Silico Molecular Docking and ADMET Study of Essential Oils of Three Vitex Species Grown in Tarai Region of Uttarakhand

Abstract

A comparative study of volatiles, antioxidant activity, phytotoxic activity, as well as in silico molecular docking and ADMET study, was conducted for essential oils from three Vitex species, viz., V. agnus-castus, V. negundo, and V. trifolia. Essential oils (OEs) extracted by hydrodistillation were subjected to compositional analysis using GC-MS. A total number of 37, 45, and 43 components were identified in V. agnus-castus, V. negundo, and V. trifolia, respectively. The antioxidant activity of EOs, assessed using different radical-scavenging (DPPH, H₂O₂ and NO), reducing power, and metal chelating assays, were found to be significant as compared with those of the standards. The phytotoxic potential of the EOs was performed in the receptor species Raphanusraphanistrum (wild radish) and the EOs showed different levels of intensity of seed germination inhibition and root and shoot length inhibition. The molecular docking study was conducted to screen the antioxidant and phytotoxic activity of the major and potent compounds against human protein target, peroxiredoxin 5, and 4-hydroxyphenylpyruvate dioxygenase protein (HPPD). Results showed good binding affinities and attributed the strongest inhibitory activity to 13-epi-manoyl oxide for both the target proteins.

Keywords: antioxidant; bioactive compounds; molecular modeling; natural products; phytotoxic; virtual ligand screening.

Figure 1

The heatmap analysis of the common essential oil constituents and tested species (The distribution of trait (common essential oil components) was identified by colors, where yellow color showed the maximum value of the trait, and blue color represented the minimum value).

Figure 2

Principal Component Analysis of tested essential oil’s chemical constituents.

Figure 3

(A–E) Antioxidant activity for essential oils of Vitex species; (A) Percent DPPH radical scavenging activity; (B) Percent H₂O₂ scavenging activity; (C) Percent NO radical scavenging activity; (D) Percent reducing power activity; (E) Percent Fe²⁺ metal chelating activity.

Figure 3

(A–E) Antioxidant activity for essential oils of Vitex species; (A) Percent DPPH radical scavenging activity; (B) Percent H₂O₂ scavenging activity; (C) Percent NO radical scavenging activity; (D) Percent reducing power activity; (E) Percent Fe²⁺ metal chelating activity.

Figure 4

(A–E) Antioxidant activity in terms of IC₅₀ values (µL/mL) for VAO, VNO, and VTO, (A) DPPH radical scavenging, (B) H₂O₂ radical scavenging, (C) NO radical scavenging, (D) reducing power activity, (E) Metal chelating activity. Statistically significant differences were examined using one-way ANOVA and Tukey posthoc tests. *** p < 0.001, ** p < 0.005, * p < 0.05 above columns indicate significant differences between treated groups. Values are mean ± SD, n = 3.

Figure 5

Correlation among chemical components of essential oils and biological activities of Vitex species (here, DPPH = percent inhibition of DPPH radical scavenging activity at 50 µL/mL; H₂O₂ = percent inhibition of H₂O₂ radical scavenging activity at 50 µL/mL; NO = percent inhibition of NO radical scavenging activity at 50 µL/mL; RPA = percent inhibition of reducing power activity at 50 µL/mL; FeMCA = percent inhibition of Fe²⁺ metal chelating activity at 50 µL/mL; SGI = percent inhibition of seed germination at 100 µL/mL; RLI = percent inhibition of root length at 100 µL/mL; SLI = percent inhibition of shoot length at 100 µL/mL.

Figure 6

(A–H) Docked conformations of molecules in the binding cavity of HPPD (PDB: 6J63) and human periredoxin 5 (PDB: 1HD2) with least binding energies. The complex established are (A) 6J63-NTBC, (B) 6J63-13-epi-manoyl oxide, (C) 6J63-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (D) 6J63-caryophyllene oxide, (E) 1HD2-ascorbic acid; (F) 1HD2-13-epi-manoyl oxide, (G) 1HD2-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (H) 1HD2-caryophyllene oxide.

Figure 6

(A–H) Docked conformations of molecules in the binding cavity of HPPD (PDB: 6J63) and human periredoxin 5 (PDB: 1HD2) with least binding energies. The complex established are (A) 6J63-NTBC, (B) 6J63-13-epi-manoyl oxide, (C) 6J63-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (D) 6J63-caryophyllene oxide, (E) 1HD2-ascorbic acid; (F) 1HD2-13-epi-manoyl oxide, (G) 1HD2-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (H) 1HD2-caryophyllene oxide.

Figure 6

(A–H) Docked conformations of molecules in the binding cavity of HPPD (PDB: 6J63) and human periredoxin 5 (PDB: 1HD2) with least binding energies. The complex established are (A) 6J63-NTBC, (B) 6J63-13-epi-manoyl oxide, (C) 6J63-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (D) 6J63-caryophyllene oxide, (E) 1HD2-ascorbic acid; (F) 1HD2-13-epi-manoyl oxide, (G) 1HD2-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (H) 1HD2-caryophyllene oxide.

Figure 6

(A–H) Docked conformations of molecules in the binding cavity of HPPD (PDB: 6J63) and human periredoxin 5 (PDB: 1HD2) with least binding energies. The complex established are (A) 6J63-NTBC, (B) 6J63-13-epi-manoyl oxide, (C) 6J63-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (D) 6J63-caryophyllene oxide, (E) 1HD2-ascorbic acid; (F) 1HD2-13-epi-manoyl oxide, (G) 1HD2-5-(1-Isopropenyl-4,5-dimethylbicyclo [4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, (H) 1HD2-caryophyllene oxide.

Figure 7

Binding energy (−kcal/mol) of selected phytocompounds from VAO, VNO, and VTO, complexed with 6J63 and 1HD2.

Figure 8

Boiled-egg graph of the selected phytoconstituents.

Figure 9

Bioavailability radar of selected phytoconstituents (pink area showed the drug likeness properties of selected compounds) 1: 1,8-cineole, 2: sabinene, 3: α-pinene, 4: α-terpinyl acetate, 5: β-farnesene, 6: viridiflorol, 7: β-caryophyllene, 8: β-iraldiene, 9: terpine-4-ol, 10: 5-(1-isopropenyl-4,5-dimethylbicyclo[4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, 11: 13-epimanoyl oxide, 12: α-phellandrene, 13: caryophyllene oxide.