No abstract

Use of different solvent systems for extraction of plant materials may cause variation in their bioactivities. The present study was conducted to evaluate the presence of different phytoconstituents and to compare in vitro bioactivities of petroleum ether, dichloromethane (DCM) and methanol extracts of Bombax ceiba (B. ceiba) roots available in Bangladesh. Preliminary phytochemical screening was conducted using specific standard procedure. Antioxidant activity of the extracts was evaluated using DPPH radical scavenging assay. Determination of total phenolic and flavonoid content was also carried out. Antibacterial and cytotoxic activities were investigated using disc diffusion method and brine shrimp lethality bioassay, respectively. All the experiments were carried out from February 2016 to September 2016. Phytochemical evaluation revealed the presence of alkaloids, terpenoids, carbohydrates, tannins, flavonoids, saponins and steroids. The methanol extract showed the highest DPPH radical scavenging activity and had the highest phenolic (187.42 ± 3.77 mg/g, GAE) and flavonoid content (74.67 ± 4 mg/g, QE) followed by the DCM and petroleum ether extracts. The extracts showed positive correlation between DPPH radical scavenging activity with the phenolic and flavonoid content. All the extracts showed mild to moderate in vitro antibacterial activity with zone of inhibition ranging from 7 mm to 13 mm. In brine shrimp lethality bioassay, the observed LC 50 values for petroleum ether, DCM and methanol extracts were 70.72 μg/ml, 37.72 μg/ml and 22.58 μg/ml, respectively which revealed strong cytotoxic potential of the extracts compared to the positive control. The results indicated that B. ceiba roots could be a very potent source of natural radical scavenger and cytotoxic agent.

The present study was designed to investigate antioxidant, antimicrobial and cytotoxic effects of petroleum ether, chloroform and hydromethanol fraction of methanol extract of Citrus aurantifolia peel. Preliminary phytochemical screening of the fractions was done following the standard procedure. Antioxidant activity was measured using DPPH free radical scavenging assay besides measuring total phenolic and flavonoid content using Folin-Ciocalteu reagent and aluminum trichloride method, respectively. The antimicrobial activity was conducted by disc diffusion method and cytotoxic activity was determined by brine shrimp lethality bioassay. The results of phytochemical screening were indicative of the presence of steroids, alkaloids, saponins, glycosides, flavonoids in the fractions. A dose dependent scavenging activity was observed in DPPH radical scavenging assay where chloroform fraction demonstrated the highest activity with IC50 value of 153.68 ± 3.60 μg/ml. The highest phenolic content was observed in chloroform fraction (308.0 ± 6.55 mg/g gallic acid equivalent) and highest flavonoid content was found in hydromethanol fraction (132.66 ± 2.36 mg/g quercetin equivalent). The chloroform fraction showed excellent antibacterial activity against all the tested bacteria where highest zone of inhibition (19 mm) was produced against Bacillus cereus. In brine shrimp lethality bioassay, LC50 values for petroleum ether, chloroform and hydromethanol fractions were 367.39 μg/ml, 228.14 μg/ml and 296.52 μg/ml, respectively. The present findings suggested that C. aurantifolia peel could be a potent source of medicinally important secondary metabolites and further investigations can be done to identify those active compounds responsible for such bioactivity. Dhaka Univ. J. Pharm. Sci. 19(2): 161-168, 2020 (December)

Background This study was designed to evaluate the free radical scavenging property of chloroform extract of the bark of Stereospermum chelonoides (SCBC) and to investigate its potential in Alzheimer's disease and inflammation, two oxidative stress related disorders. Methods Preliminary phytochemical analysis and in vitro antioxidant potential of SCBC were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay, cupric reducing antioxidant capacity (CUPRAC) and total antioxidant capacity determination assay. Total phenol and total flavonoid contents were also determined. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based cytotoxicity and cyto-protective assays were performed on human neuroblastoma SH-SY5Y cells. Thioflavin-T assay and caspase activation measurement assay were carried out to elucidate the mechanism of cytoprotection of SCBC observed here. In vivo anti-inflammatory potential was measured using croton oil and xylene induced ear edema tests. Results Phytochemical screening of SCBC revealed the presence of various phytoconstituents. Dose-dependent in vitro antioxidant activity was observed. The extract was enriched in flavonoids and polyphenolic compounds too. SCBC was found to inhibit amyloid-β peptide 1-42 (Aβ42) induced cell death in a dose-dependent manner. Encouraged by the cyto-protective effect, its effects on Aβ42 fibrillogenesis and caspase-3 activated apoptosis were observed. SCBC significantly slowed down the Aβ42 fibrillogenesis and caspase-3 activation in a concentration-dependent manner indicating its probable mechanism of rendering cyto-protection. SCBC has been able to reduce inflammation significantly in croton oil induced ear edema in both doses. Conclusions Thus, this study could form the basis for further study for the potential use of SCBC in oxidative stress associated cell death and inflammation.