Chemical analysis of Ricinus communis L. (Euphorbiaceace) seed kernel extract and its in-vitro toxicity in two Podagrica Species (Coleoptera: Chrysomelidae)

Abstract

Since synthetic pesticides are associated with many toxicological problems against untargeted subjects, pesticides from botanical sources become a better option. This study obtained R. communis seed kernel extract (RCSKE) through acidified aqueous extraction. The extract was screened using Infra red (IR) and Ultraviolet (UV) spectroscopy, High-Performance Liquid Chromatography (HPLC) and Cass Chromatography (GC) for bioactive agents. In-vitro effects of RCSKE, chlorpyrifos (CPF) and cypermethrin (CYPER-M) on superoxide dismutase (SOD), Catalase (CAT), acetylcholinesterase (AChE) and Carboxylesterase (CE) activities in Podagrica sjosdteti and Podagrica uniforma were determined spectrophotometrically. The IR and UV of RCSKE majorly depict the presence of aromatic ring, ethylenic bond, carbonyl bond, hydroxyl and carboxylic groups. The HPLC and GC majorly show the presence of ricinoleic acid, ricinine and ricin. The RCSKE, CYPER-M and CPF increased CAT activity in P. sjosdteti, but reduced it in P. uniforma. The RCSKE and CYPER-M significantly reduced SOD, and elevated AChE activities in P. sjosdteti. The IC₅₀ values of RCSKE, CYPER-M and CPF against CE activity in P. sjosdteti were IC₅₀ = 2.66 µg/ml, IC₅₀ = 2.37µg/ml and IC₅₀ = 2.65 µg/ml), respectively, while that of RCSKE against P. uniforma was IC₅₀ = 2.49 µg/ml. This study suggests that the extract of Ricinus communis seed kernel contains bioactive substances, capable to inhibit the antioxidant, acetylcholinesterase and carboxylesterase enzymes in Podagrica species flea beetles, comparable to commercial pesticides, Cypermethrin and Chlorpyrifos.

Key words: Ricinus communis, Chemical screening, Podagrica sjosdteti, Podagrica uniforma, antioxidant enzymes, hydrolytic enzymes

DOI: 10.7176/ALST/75-05

Publication date:June 30^th 2019