Antioxidative activities of Capsicum spp. and varieties

Kusumarn Noipha, D. of Biomedical Sci, F. of Medicine, PSU.
Vipavadee Prasartthong, D. of Biomedical Sci, F. of Medicine, PSU.
Suvina Ratanachaiyavong, D. of Biomedical Sci, F. of Medicine, PSU.
Corresponding e-mail : rsuvina@ratree.psu.ac.th

Grant : Government Budget
Presented : The 2nd Bio-System Symposium and Workshop, Faculty of Science, Khon Kaen University, 3-7 July 2000
Key words : antioxidant, Capsicum spp., NBT (nitroblue tetrazolium) assay, DPPH (diphenylpicrylhydrazyl) assay

Capsicum, the fruit of the family Solanaceae generally known as Chilli, has been used widely and extensively in cooking. Beside its spicy property and lovely color for cooking, the medicinal benefits of Capsaicin, the major capsaicinoid compounds in chilli has been described. Moreover, chilli is also a rich source of vitamin C, a chemical substance capable of removing free radicals. This has brought us interest to study the antioxidative activities of the Capsicum varieties, using two different methods of nitroblue tetrazolium (NBT) photochemical reduction and the DPPH (diphenyl-picrylhydrazyl) radical scavenging assays. Five varieties of Capsicum spp. namely : BirdŐs eye chillies -Prik Kie Nhu (green and red fruits), -Prik Shee (young and mature fruits), Anaheim chilies; Prik Shie Fah (green and red fruits), Prik Leung (yellow wax) and the Mexican chili -Prik Yourk were extracted with 50 mM phosphate buffer (0.1 mM EDTA, 0.3% Triton X-100, 4.0% PVP 10) at 3 ml/gram of wet weight with 20 min 23,000 g centrifugation and the 4oC overnight dialysate were kept at -70oC until used.
The total superoxide and DPPH radical scavenging activities of crude extracts were expressed as Units/gram wet weight (1 Unit = 50% inhibition of scarvenging activity under specific conditions of assay equivalent to 190 mM Trolox) were shown in table below. 
Capsicum spp		Total SODs activity	DPPH radical	scavenging activity

	varieties		Units/g wet weight	% inhibition	Units/g wet weight

	Prik Kie-Nhu	- Green	694.1	78.65,   74.36	36.7
                       		- Red	876.7	75.01,   61.26	38.2
	Prik Shee	- young 	678.1	75.61,   60.75	 34.2
                		- mature 	688.8	83.50,   72.92	43.0
	Prik Shie-Fah	- Green	523.8	78.30,   86.73	51.1
                        		- Red	627.6	55.35,   53.17	33.1
	Prik Leung (Yellow wax)	602.2	74.71	42.4
	Prik Youk (Mexican chilli)	479.1	75.07	51.5
There was no correlation on antioxidative activities in crude extracts of Capsicum measured by the two assays. Though the method for sample preparation described here in this study was selected for the retaining of most SODs activities, most samples still contained antioxidative activity measurable by the DPPH assay. This study demonstrated the important on the appropriate selection of assay for determining the major constituent of antioxidative compounds in natural products. The combination use of appropriate assays should be considered for the total antioxidative activity measurement.
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