Identification and Characterization of Antioxidant and Cytotoxic Activities of Selected Medicinal Plants of Gallyat Region, Pakistan

Abstract

Human have always relied on biological products and have continuously explored their potential to improve various aspects of humanlives.The research on natural product is one of the key of discovering bioactive natural substances. Since with little knowledge about the etiology of many human, animals and plants disorders, this become difficult to synthesized potentially active substance in the chemical laboratory for their treatment. The bioactive compounds obtained from natural sourcesprovideharmonizingattributes to synthetic compounds with respect to their composition, size, different functional groups, architectural and stereo chemical complexity. Importantly, these bioactive natural substances have potential to serve functions in specific biological system like scavenging of free radicals, inhibiting the tumor etc.Medicinal plants have been playing a vital role in combating various ailments including cancer. Many modern antitumor and anticancer drugs have plant-based origin. e.g.Podophyllotoxin (Podophyllumpeltatum), Vincristine (Catharanthusroseus) etc.Study area i.e. Gallyat region has rich diversity of medicinal plants. Five ethnomedicinally important plant species (Dryopterisramosa, Quercusleucotricophora, Bidensbiternata, Arisaemaflavum and Rosa brunonii) were selected from the study which were never been assessed for their antioxidant and cytotoxic potential. The selected plant species were collected from Gallyat region of Pakistan, identified and voucher specimens were deposited in herbarium of Quaid-i-Azam University Islamabad for future references.Crudemethanolic extract (CME) of each selected plant was prepared using maceration technique and each plant extract was evaluated for its antioxidant

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and cytotoxic potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Brine shrimp lethality (BSL) assay and Potato disc antitumor (PDA) assay respectively.The CME of D. ramosa showed maximum free radical scavenging potential (IC5088.67±0.73 µg/mL) followed by CME of Q. leucotricophora(IC5095.51±0.19µg/mL)and R. brunonii (IC50131.41±0.18 µg/mL). CME of A. flavum and B. biternata showed minimum free radical scavenging potential. The crude extract of R. brunonii showed highest cytotoxicity against Brine shrimps than all other crude extracts at all concentrations tested.The maximum antitumor potential was shown by crude extract of R. brunonii(IC50 655.65µg/mL) followed by D. ramosa (IC50 790.51µg.mL) and A. flavum (IC50 825.94 µg/mL).The CME of D. ramosa and R. brunonii were subjected to polarity based solvent-solvent fractionation. All fractions [n-hexan fraction (nHF), Chloroform fraction (CF), Ethl acetate fraction (EF) and Aqueous fraction (AF)] so obtained were assessed for antioxidant and cytotoxic potential. The maximum antioxidant potential was showed by EF of D. ramosa (IC50 57.85±0.24µg/mL) followed by AF of same plant (IC50 108.98±0.28µg/mL). The EF of R. brunonii showed maximum cytotoxicity (LD50405.43±4.8µg/mL) followed by AF of D. ramosa (LD50830.95±2.0µg/mL). The maximum tumor inhibition in PDA was showed by EF of R. brunonii(753.68±0.48µg/mL) followed by AF of D. ramosa (793.23±0.31µg/mL) and EF of D. ramosa (834.99±0.24µg/mL). In comparison with control, the vincristine a well-known antitumor pure compound showed IC50 232.34±0.58µg/mL. The EF and AF of D. ramosa and EF of R. brunonii were subjected to different chromatographic techniques (CC, HPLC, TLC, PTLC etc.) in order to isolate pure compounds. Iriflophenone-3-C-β-D- glucopyranoside,

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Mangiferrin, iso-mangiferrin and Astragalin were isolated from selected fractions D. ramosawhile Quercetin-3-O-rhamnoside, Kampferol-3-O-β-glucopyranoside and Tilirosidewere isolated from ethyl acetate fraction of R. brunonii. The structure of isolated compounds were determine by UV-Vis spectroscopy, MS, FT-IR, 1-D NMR (1H, 13C, DEPT) and 2-D NMR (COSY, HSQC, HMBC). All the isolated compounds showed high antioxidant potential except tiliroside (IC50923.67± 0.86µg/mL) while tiliroside showed excellent cytotoxic potential (LD5050.42± 0.88µg/mL). This is the first report of antioxidant and cytotoxic activities and isolation of compounds from D. ramosa and R. brunonii to the best of our knowledge. Further in-vivo and in-vitro testing of these isolated compounds is recommended. They may prove to be the potential future drugs.