Analysis of Volatile Secondary Metabolites in Ocimum basilicum Cell Suspensions: Inhibition, In Silico Molecular Docking, and an ADMET Analysis against Proteolytic Enzymes of Rhynchophorus ferrugineus

Abstract

Our study’s overarching goal was to determine which O. basilicum cell suspensions approach yielded the most insecticidal and R. ferrugineus-inhibitory volatile secondary metabolites. After inoculation with Verticillium dahliae as an activator, the growth kinetics were measured, and the extract was identified using GC-MS. Validation was achieved for the insecticidal efficacy of a volatile extract, the pure phenolic content against larva and adult R. ferrugineus, and the inhibitory effect on proteases (in vivo and in vitro). The volatile extract achieved an LC50 of 1229 µg/mL and an LD50 of 13.8 µg/larva. The LC50 values for β-bergamotene, α-eudesmol, β-farnesene, linalool, 1,8-cineole, eugenol, α-guaiene, and β-caryophyllene were 1294, 1312, 1356, 1398, 1426, 1459, 1491, and 1523 g/mL, respectively. The LD50 activities of α-eudesmol, linalool, 1,8-cineole, eugenol, and nerol were 12.4, 13.7, 13.9, 14.2, and 15.6 g/larva, respectively. Active volatile extract of O. basilicum inhibited trypsin proteinase, elastase, cysteine, overall protease, and metalloprotease activity with IC50 values of 89.4, 101.7, 394.7, 112.4, and 535.2 µg/mL and 178.5, 192.4, 547.3, 208.3, and 924.8 µg/mL, in vitro and in vivo, respectively. There was evidence of action against total proteases (in vitro) with IC50 values of 78.9, 81.2, 88.6, 90.7, 91.5, 97.6, 107.4, and 176.3 µg/mL for β-bergamotene, α-eudesmol, β-farnesene, linalool, 1,8-cineole, eugenol, α-guaiene, and β-caryophyllene, respectively. Total proteases (in vivo) are inhibited by the α-eudesmol, linalool, 1,8-cineole, eugenol, nerol, and (E)-β-ocimene, with IC50 values of 162.3, 192.7, 193.1, 201.4, 248.6, and 273.2 µg/mL, respectively. ADMET and molecular docking modeling were the only two methods used to conduct in-depth computational analyses of compounds. The study recommended using an efficient cell suspension method to produce a volatile extract rich in useful secondary metabolites that may be utilized as a bio-insecticide.