TOTAL PHENOLIC AND FLAVONOID CONTENTS, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF ORGANIC ROSE ETHANOL EXTRACTS

Abstract

The objectives of this research were to study total phenolic and flavonoid contents, antioxidant and antibacterial activities of ethanol extracts from 3 varieties of roses, Mon Dang Prasert (Rosa damascena cv. Dang Prasert), Mon Klai Kangwon (Rosa damascena cv. Klai Kangwon) and Bishop’s castle (Rosa hybrid cv. Bishop’s castle) which are grown with organic agriculture by farmers in Chiang Dao District, Chiang Mai Province. The total phenol content was determined by Folin-Ciocalteu colorimetry, total flavonoid content by Aluminum chloride colorimetric assay, antioxidant activity by DPPH method and antibacterial activity by Agar well diffusion method. It was found that the extracts of Mon Dang Prasert, Mon Klai Kangwon and Bishop’s castle showed total phenolic contents of 606.60, 92.31, and 101.93 mg GAE/g extract, respectively. Total flavonoid contents of the Mon Dang Prasert, Mon Klai Kangwon and Bishop’s castle extracts were 178.76, 42.99 and 38.62 mg QE/g extract, respectively. The antioxidant activity showed IC₅₀ values of 7.40, 25, and 30 µg/mL, respectively, using vitamin C and trolox as standard compounds. The Mon Dang Prasert, Mon Klai Kangwon and Bishop’s castle extracts were found to inhibit the growth of two gram-positive bacteria, Staphylococcus aureus and Bacillus cereus, and inhibit the growth of one type of Gram-negative bacteria, Proteus mirabilis. All extracts were inactive to inhibit the growth of Escherichia coli, a Gram-negative bacteria. The results of this study can be used as information for developing health supplement products in the future.