Bioefficacy Of Extracts Research Articles

Repellent, antifeedant and toxic effects of plants-extracts against Spodoptera frugiperda larvae (fall armyworm)

The fall armyworm (FAW), Spodoptera frugiperda, is a polyphagous pest because of the damage it causes to crops. The utilization of plant extracts with bioactive compounds for controlling S. frugiperda has been emerging to be a new venture. Therefore, this study aimed at analyse the impact of Adathoda vassica, Dathura metel, and Tagetes erecta extracts against FAW. Leaves were washed, air dried (27 ± 2○C) and powdered and their extracts were obtained with ethyl acetate as a solvent. Bio efficacy of extracts was studied through different concentrations (0.2, 0.4, 0.6 μg/μL) against third instar larvae of S. frugiperda to assess the contact toxicity, antifeedant activity and repellency effect. The presence of phytochemicals i.e; tannins, terpenoids, phenols, saponins, flavonoids and alkaloids were determined and characterized using FTIR analysis. The T. erecta was more effective against FAW larvae that caused significantly very high (P < 0.05) antifeedant activity, and contact toxicity with the lowest LD50 (at all concentrations). The degree of repellency was greatly influenced by the concentration of the extract. Low Index of Repellency (IR), high Percent Repellency (PR) and residual PR were observed in T.erecta and D.metel and the highest significant value (P < 0.05) was observed in T.erecta. Therefore, T.erecta can be categorized into the highest repellency class (Class V). The phytochemical and FTIR analysis confirmed the presence of bioactive compounds having the potential against S. frugiperda. Therefore, D.metel and T. erecta are showing the potentiality for pesticidal development.

Effect of Storage Temperature on Bio efficacy of Aqueous Extract of Ganoderma lucidum

Stability testing is key requirement in the drug development process along with storage temperature which may deteriorate bio-constituents and efficacy of natural products. Aqueous extract of Ganoderma lucidum has revealed pharmacological effects against high altitude stressors and has potential for mitigating high altitude maladies. In the present study, the extract of Ganoderma lucidum was stored at different storage conditions such as room temperature, 4 °C and -20 °C for two year and qualitative and quantitative analysis of bio-constituents and bio-efficacy was carried out. No significant change was observed in any extract kept in different temperature conditions in terms of its polysaccharide, phenolic and flavonoids content. The extract kept at room temperature absorbed slight moisture in few samples but no change in overall polysaccharide, phenolic and flavonoids content was recorded. The moisture absorption problem was not observed in extracts stored at 4 °C and -20 °C. The bio-efficacy of the extract at room temperature, 4 °C or -20 °C were comparable to the freshly prepared extract and the data from the studies suggest that extract has good shelf life up to two year without loss of bio-efficacy. Overall, the extract retained its bio-efficacy for two years at different temperature storage conditions.