Phytochemical Analysis and Possible Synergistic Interactions of Vitex agnus-castus L., Vitex negundo L., and Piper longum L. Essential oils on Pesticidal Activities
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Date
2023-07
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G. B. Pant University of Agriculture & Technology, Pantnagar-263145
Abstract
This study focused on the phytochemical analysis and possible synergistic interactions
of EOs from Piper longum L., Vitex negundo L., and Vitex agnus-castus L. on pesticidal
activities. The plant material was collected from the Tarai region of Uttarakhand. The EOs
were extracted through hydro-distillation using a Clevenger type of apparatus. The EOs
yields obtained from 0.04% to 0.42%. The phytochemical analysis of the EOs was done by
GC and GC-MS. The GC-MS analysis of PLAO, VNAO, and VACAO identified 37, 97,
and 47 compounds constituting 98.8%, 98.8%, and 99.8% of the total EOs. The major
compounds identified in PLAO were β-pinene, cis-nerolidol, 2-heptyl acetate, α-pinene,
(E)-caryophyllene, limonene, 2-undecanone, b-eudesmol, linalool, camphene, etc.
Viridiflorol, β-caryophyllene, labd-8-en-15-oic acid, ethyl ester, 5-(1-isopropenyl-4,5-
dimethyl bicyclo[4.3.0]nonan-5-yl)-3-methyl-2-pentenol acetate, caryophyllene oxide, 2-
trans-octenol, trans-β-ocimene, 4-terpineol, and phytol, etc. were identified as major
compounds in VNAO. Similarly, 1,8-cineole, (E)-β-ocimene, α-terpinyl acetate, terpinen-4-
ol, (Z)-β-ocimene, α-terpineol, β-caryophyllene, trans-β-farnesene, g-terpinene, etc. were
identified as major compounds in VACAO. The recovered EOs were blended in binary and
ternary mixtures at equal ratios to analyze their synergistic interactions on pesticidal
activities. The nematicidal and antifungal activities of the EOs were evaluated using
standard protocols. The nematicidal activity of the individual EOs and their combinations
was assessed against root-knot nematodes M. incognita at different concentrations (0.25,
0.5, and 1 μL/mL). The antifungal activity of pure and blended EOs was also tested against
two phytopathogenic fungi, Rhizoctonia solani, and Sclerotinia rolfsii, using the discdiffusion
technique at different concentrations (40, 60, and 80 μL/mL). Furthermore, a
molecular docking study was conducted on the major compounds of the EOs to investigate
their interactions with target proteins in comparison with standard inhibitors physostigmine
(AChE), ethacrynic acid (GST-1), and 14 α-demethylase enzyme (CYP51). Overall, this
study provides valuable information into the nematicidal and antifungal potential of PLAO,
VNAO, VACAO, and their binary or ternary combinations. The results of our investigation
confirm synergistic interactions among the tested EOs. These findings will be implications
for sustainable agriculture and the development of natural products with pesticidal
properties.
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Theses of M.Sc.