In vitro anti-oxidant and anti-adhesin assays of n-hexane and methanolic extracts of Caryota no seeds

Abstract

Abstract To determine the anti-oxidant and anti-adhesin activities of the n-hexane and methanolic extracts of Caryota no (CN) seeds. For anti-adhesin properties, the wells of a sterile flat-bottomed tissue culture plate were filled with 200µL of each extract in several concentrations, incubated and washed twice. 200µL of bacterial suspension was added, incubated and washed thrice with PBS. Adherent bacteria were fixed with methanol, plates emptied, left to dry and stained with crystal violet. Excess stain was rinsed under running water, air dried, bound dye resolubilized with glacial acetic acid, and the absorbance measured using a microplate reader to calculate the percentage inhibition. For antioxidant properties, three different concentrations of the DPPH solution were prepared. 2 mg of each extract was weighed out and dissolved in 10 mL of their corresponding solvent. 1 mL of DPPH solution was added to 2 ml solution of the extracts and ascorbic acid. The reaction mixture was vortexed and left in the dark for 30 minutes then absorbance was measured against blank solution to calculate the percentage scavenging radical inhibition. Statistical difference was presumed at P < 0.05. The extracts showed significant (P < 0.05) adhesin inhibition activities, n-hexane (64%) and methanolic (46%) at 200µg/mL concentrations. The fractions of the extracts also showed various remarkable results. The anti-adhesin activity increased with increasing extract concentration in both extracts. Antioxidant assays revealed that at 200 mg/mL, both extracts were significantly (P < 0.05) lower than the control. Both the n-hexane and methanolic extracts showed remarkable adhesin inhibition activities at concentration of 200 µg/mL and antioxidant effects, with the methanolic extract demonstrating comparable levels as the standard, ascorbic acid. This implies that both extracts may serve as veritable natural sources of anti-adhesins, antioxidants and thus adjunct anti-infective agents or immune enhancers. Keywords DPPH, Caryota no, Adhesin, Reactive oxygen species, anti-oxidant