Antimicrobial Activity and Brine Shrimp Lethality Bioassay of the Leaves Extract of Dillenia indica Linn

The crude methanolic extract of Dillenia indica Linn. (Dilleniaceae) leaves has been investigated for the evaluation of antimicrobial and cytotoxic activities. Organic solvent (n-hexane, carbon tetrachloride and chloroform) fractions of methanolic extract and methanolic fraction (aqueous) were screened for their antimicrobial activity by disc diffusion method. Besides, the fractions were screened for cytotoxic activity using brine shrimp (Artemia salina) lethality bioassay. Among the four fractions tested, n-hexane, carbon tetrachloride, and chloroform fractions showed moderate antibacterial and antifungal activity compared to standard antibiotic, kanamycin. The average zone of inhibition was ranged from 6 to 8 mm at a concentration of 400 µg/disc. But the aqueous fraction was found to be insensitive to microbial growth. Compared to vincristine sulfate (with LC50 of 0.52 µg/ ml), n-hexane and chloroform fractions demonstrated a significant cytotoxic activity (having LC50 of 1.94 µg/ml and 2.13 µg/ml, respectively). The LC50 values of the carbon tetrachloride and aqueous fraction were 4.46 µg/ml and 5.13 µg/ ml, respectively. The study confirms the moderate antimicrobial and potent cytotoxic activities of Dillenia indica leaves extract and therefore demands the isolation of active principles and thorough bioassay

Phytochemical Screening and In vitro Evaluation of Pharmacological Activities of Aphanamixis polystachya (Wall) Parker Fruit Extracts

Purpose: To investigate the crude n-hexane, ethyl acetate and methanol extracts of Aphanamixis polystachya fruit for their cytotoxic, antimicrobial, antioxidant and thrombolytic activities. Methods: The fruit extracts were screened for major phytochemical compounds using in vitro established procedures. Antimicrobial and cytotoxic studies of the fruit extracts were conducted using disc diffusion and brine shrimp lethality bioassay methods, respectively, while an in vitro thrombolytic model was used to assess the clot lysis effect of the extracts with streptokinase as positive control. Antioxidant activity was evaluated by free radical scavenging activity using 2, 2-diphenyl-1- picrylhydrazyl (DPPH) and nitric oxide assay as well as total phenolic content. Results: The fruit extracts were a rich source of phytochemicals and among the extracts n-hexane extract showed highest antimicrobial activity against Shigella dysenteriae (zone of inhibition: 9.7±0.2 mm) and Candida albicans (zone of inhibition: 8.8±0.3 mm) at a concentration of 1000μg/disc, whereas at the same concentration methanol extract showed highest zone of inhibition, 10.1±0.4mm, against Staphylococcus aureus. Compared to potassium permanganate with a median lethal concentration (LC50) of 13.23 μg/ml in the brine shrimp lethality assay, the LC50 of n-hexane, ethyl acetate and methanol extracts were 15.77, 17.51 and 141.37 μg/ml, respectively. All the extracts showed significant clot lysis activity (p < 0.001) with reference to negative control and % clot lysis of the extracts were approximately 13. Notable antioxidant activity of the methanol extract was observed unlike the other extracts. Conclusion: The results of the study demonstrated the potential cytotoxic, thrombolytic and antioxidant activities of the fruit extracts of A. polystachya and therefore further studies on the isolation and identification of active principles are required