ABSTRACT
Recently, the residues or by-products of agriculture industry take attention for their valuable source of natural antioxidants. Taif rose (Rosa damascena trigintipetala Dieck) is considered one of the most important economic products of Taif, Saudi Arabia. In this study, the antioxidant and total phenolic contents of the defatted flowers of fresh Taif rose were investigated. The antioxidant activity was chemically determined using three methods; 1,1-diphenyl picrylhydrazyl (DPPH.) free radical scavenging activity, phosphomolybdenum method and reducing power activity. The methanol extract showed antiradical activity with SC50=49.44 g/ml. Different fractions obtained from successive fractionation of the methanol extract with organic solvents of different polarities; chloroform (CHCl3), ethyl acetate (EtOAc) and n-butanol (n-BuOH); showed that, the EtOAc fraction had higher antiradical activity than n-BuOH fraction, and their respective SC50 were 15.62 and 36.29 g/ml. On the other hand, CHCl3 fraction had a poor antiradical activity (SC50>100 g/ml). The total phenolics, flavonoids, flavonols and RPHPLC analysis of the methanol extract and its EtOAc and n-BuOH fractions were determined. The ethyl acetate fraction had the highest contents of phenolics, flavonoids and flavonols that correlated with the antioxidant activity. From this work, it is obvious that the by-product from concrete oil production of Taif rose could be used as a good inexpensive source of antioxidant polyphenolics.
ABSTRACT
The use of plants and their derived substances increases day by day for the discovery of new therapeutic agents owing to their versatile applications. Conocarpus erectus L. (family Combretaceae) is one of two species in the genus Conocarpus widely spread in Taif and other parts of the Kingdom of Saudi Arabia. It is used in some countries as folk remedy for anemia, catarrh, conjunctivitis, diabetes, diarrhea and fever. To our knowledge from literatures there is little work about phytochemical contents and biological activities of C. erectus which encouraged the authors to carry out this study. The four defatted methanol extracts of C. erectus different parts (leaves, stems, fruits and flowers) showed high free radical scavenging activity toward DPPH radical with SC50 between 6.47-9.4 μg/ml. The n- BuOH fractions obtained from successive fractionation of the four defatted methanol extracts had radical scavenging activity with SC50 between 4.43-5.89 μg/ml higher than the EtOAc fractions (7.04-10.71 μg/ml). Due to the high antioxidant activity of the EtOAc and n-BuOH fractions, it was in vitro assayed toward two human cancer cell lines; HepG2 & MCF-7; using Sulphorhodamine-B assay method. The results showed that most fractions had cytotoxic activity with IC50< 20μg/ml which fall within the American Cancer Institute criteria. A preliminary antibacterial screening of the four defatted methanol extracts of the different parts toward five bacterial strains were done. Phytochemical investigation of the EtOAc and n-BuOH fractions showed that phenolic compounds constitute the major components of it. In conclusion this is the first report on the phytochemical and biological properties of Conocarpus erectus growing in Taif governorate, KSA. More in vivo and in vitro studies along with detailed phytochemical investigation are needed in the hope to can use this plant (crude extract, fractions, sub-fractions or pure compounds) in the prevention and therapies of some diseases.