Estimation of Total Carotenoids and Free Radical Scavenging Activity of Selected Vegetables

Background: Vegetables are known for their rich carotenoid content responsible for their antioxidant properties. Objectives: This study sought to estimate the total carotenoid content (TCC) in four edible Nigerian vegetables; compare their free radical scavenging activity (FRSA) and relate their TCC to their respective FRSA. Methods: The method employed for extraction involved homogenization with ethanol using a blender. Estimation of the TCC was obtained by an equation derived from their Chlorophyll A and B contents from reading absorbances of homogenates at 470nm; 649nm and 665nm. FRSA of ethanolic homogenates on 2;2-diphenyl-1- picrylhydrazyl (DPPH) by decreased absorbance of 1mM DPPH on adding extracts was read at 517nm. The FRSA obtained by 0.2-1% concentrations done in triplicates was compared statistically (ANOVA Test; p0.01). Mean Inhibitory concentration (IC50) value was obtained graphically via percentage inhibition/concentration curve. Results: Capsicum annum had the highest TCC compared to the other vegetables. Carica papaya leaves exhibited a superior FRSA compared to other plants (p0.0001). Results showed that there may be a direct relationship between TCC and FRSA. However; Carica papaya which had the highest FRSA did not show a high TCC. Hence; Carica papaya may possess other phytochemicals other than carotenoids responsible for its high FRSA. Conclusion: This study shows that Carica papaya leaves had a high FRSA and antioxidant capacity due to the presence of carotenoids and other beneficial phytochemicals. This evidence supports the fact that it can be included into our diet as Africans

Antisickling properties of the fermented mixture of Carica papaya Linn and Sorghum bicolor (L.) Moench

The antisickling properties of fermented mixture of dried unripe fruit pulp of Carica papaya and dried Sorghum bicolor leaves; mixed in equal proportions in distilled water; was carried out using sodium metabisulphite sickled red blood cells and the result presented. Equal weight of dried C. papaya fruit pulp and S. bicolor leaves were fermented together in distilled water at room temperature and the aqueous extract obtained and used for antisickling assays. The extract gotten from the materials incubated for 5 days indicated as SP5; was found to have the highest antisickling properties with 93inhibitory and 84reversal activities. The concentration of the day 5 extract was further varied. 0.2 ml was found to be the optimum volume of the test extracts

Phytochemical Screening and Antioxidant Activities of some Selected Medicinal Plants Used for Malaria Therapy in Southwestern Nigeria

Purpose: Oxidative stress has been shown to play an important role in the development of anaemia in malaria. Indeed; increase in total antioxidant status has been shown to be important in recovery from malaria. The antioxidant activities of four medicinal plants traditionally used in the treatment of malaria in southwestern Nigeria were determi- ned. Methods: The ethanolic extracts of the leaves of Carica papaya Linn. [Caricaceae] ; stem bark of Magnifera indica Linn. [Anacardiaceae]; leaves of Psidium guajava Linn. [Myrtaceae] and the leaves of Vernonia amygdalina Del. [Compositae]; were used in the present study. The plant parts commonly used in the locality in malaria therapy were employed in this study. The plants were screened for the presence of phytochemicals and; their effect on 2;2-Diphenyl-1-picryl-hydrazyl radical (DPPH) was used to determine their free radical scavenging activity. Results: Phytochemical screening of the plants showed the presence of flavonoids; terpenoids; saponins; tannins and reducing sugars. M. indica did not contain cardiac glycosides and alkaloids while; P. guajava also showed the absence of alkaloids and anthraquinones. Anthraquinones was similarly absent from V. amygdalina. Concentrations of the plant extracts required for 50inhibition of DPPH radical scavenging effect (IC50) were recorded as 0.04 mg/ml; 0.313 mg/ml; 0.58 mg/ml; 2.30 mg/ml and 0.054 mg/ml for P. guajava; M. Indica; C. papaya; V. amygdalina and Vitamin C; respectively. Conclusion : All the plants showed potent inhibition of DPPH radical scavenging activity; P. guajava being the most potent. The free radical scavenging (antioxidant) activities of these plants probably contribute to the effectiveness of the above plants in malaria therapy