<i>In vitro</i> antioxidant and antidiarrheal activities of aqueous and <i>n</i>-hexane extracts of <i>Cucurbita maxima</i> seed in castor oil-induced diarrheal rats

Abstract

Diarrhea is a common health complaint occurring with mild, temporary conditions to a potentially life-threatening condition. <i>Cucurbita maxima</i> (Cucurbitaceae) seed is reportedly used traditionally for the treatment of diarrheal and thus this study aimed to evaluate the in vitro antioxidants, total tannins, phenolics contents, and antidiarrheal potentials of <i>n</i>-hexane and aqueous <i>C. maxima</i> seed extracts in castor oil induced diarrheal rats. The <i>n</i>-hexane extract mainly contains oils while the aqueous extract was thick, brown solid. The aqueous and <i>n</i>-hexane seed extract of <i>C. maxima</i> expressed significant 2,2, diphenyl-1-picrythdrazyl (DPPH) scavenging activities at 6.25 – 1000 mg/mL with IC₅₀ values of 104.01 mg/mL, 29.27 mg/mL and 26.78 mg/mL for <i>n</i>-hexane, aqueous and vitamin C respectively. The hydroxyl radical scavenging activities of the <i>n</i>-hexane and aqueous seed extract of <i>C. maxima</i> were significantly lower at higher concentrations compared with that of vitamin C. Furthermore, the total antioxidant capacities of <i>n</i>-hexane (22.08mg/mL) and aqueous seed extract (11.03 mg/mL) of <i>C. maxima</i> were found to be higher than that of vitamin C (134.46 mg/mL). The aqueous extracts (658.33±380.08 mg QE/g) total tannins were not significantly different from the <i>n</i>-hexane extract (468.33±102.55 mg QE/g) while the <i>n</i>-hexane extract contains significantly higher total phenolics (2.93±1.25 mg GAE/g) compared with the aqueous extract (0.19±0.04 mg GAE/g). Percentage inhibition of stooling was found to be 57±22%, 41±16%, and 46±11% for loperamide, <i>n</i>-hexane, and aqueous respectively. The study concludes that aqueous and n-hexane seed extracts of <i>C. maxima</i> (pumpkin) possess in vitro antioxidant activities and antidiarrheal properties.