Antimutagenic and antioxidative activities of some flowers

Abstract

The objectives of this study were aimed to determine the cytotoxicity of methanol and water extracts of red hibiscus (Hibiscus rosa-sinensis Linn.), Mexican creeper (Antigonon leptopus Hook. & Arn.), ixora (Ixora coccinea Linn.), white frangipani (Plumeria obtusa Linn.), malay apple (Syzygium malaccense (Linn.) Merr.& Perry), kra chiew (Curcuma sessilis Gage), sacred lotus (Nelumbo nucifera Gaertn.), Indian cork tree (Millingtonia hortensis Linn.), thong pun chang (Rhinacanthus nasutus ((Linn.) Kurz.) and pomegranate (Punica granatum Linn.) in the brine shrimp. It was found that most flower extracts were not cytotoxic. Antioxidant activity of flower extracts was assessed by using two methods: scavenging capacity (DPPH) and ferric reducing antioxidant power (FRAP). The content of phenolic compound in the flower extracts was also determined using Folin-Ciocalteu reagent. Water extract of ixora exhibited the strongest antioxidant activity (FRAP assay) and showed the highest total phenolic content. This study was also aimed to determine the antimutagenicity of flower extracts against the product of the reaction mixture of 1-aminopyrene-nitrite model in the absence of metabolic activation on Salmonella typhimurium strains TA 98 and TA 100 in the Ames test. The antimutagenic potential against urethane induced somatic mutation and recombination test (SMART) using Drosophila melanogaster was also performed. The results showed that none of the samples was mutagenic in the Ames test and SMART. Most of the extracts were mutagenic after nitrite treatment. Nitrite treated methanol extract of sacred lotus exhibited the highest mutagenicity on both strains in the Ames test. It induced 1194 revertants of 3.2 mg of sample per plate on TA 98 and 992 revertants of 1.6 mg of sample per plate on TA 100. However, dichloromethane extracts of red hibiscus, white frangipani, malay apple, methanol extract of malay apple and water extract of red hibiscus were an exception because they were not mutagenic after nitrite treatment. All the dichloromethane extracts of flowers decreased the mutagenicity of the reaction mixture of 1-aminopyrene nitrite model on both tester strains. Methanol extract of kra chiew and pomegranate (15 mg/plate) showed the highest antimutagenic activity in TA 98 (98%) and TA 100 (100%), respectively. It was found that the water extract of ixora was the strongest antimutagenic activity in the SMART. The protective effects of these flower extracts may be due to the presence of flavonoids and triterpenes which exerted the antioxidant activity. The finding from this study suggested that the flower extracts minimize the risk of exposure to any mutagens possibly be due to their antioxidant activity.