Evaluation of Antiocidant and Anti-Cancer Activities of Diplazium Esculentum and Stenochlaena Palustris as Functional Food / Dk Siti Hazimah Binti Pg Sharifulazar

submitted in fulfilment if the requirements for the degree of Master of Science

Abstract

Brunei medicinal plants, Diplazium esculentum and Stenochlaena palustris, are two of the several underutilised plant species. Most available records covered the ethnobotanical aspect and claims of traditional medicine, however, there is still lack of scientific information. In this study, we analysed the crude extracts using five different solvents (aqueous, chloroform, ethyl acetate, hexane and methanol), in two different extraction methods: 24-hour stirring and Soxhlet, to observe qualitative differences on phytochemicals, and quantitative antioxidant activities using DPPH, ABTS, FRAP, TPC, TFdC and TFC assays. We also conducted a single-dose cytotoxic activity initial screening using WST-8 colorimetric assay coupled with nutrient starvation study. To diversify the application of these plant species, development of functional herbal tea was conducted and paired together with five commercial teas (black tea, green tea, oolong tea, puer tea and Sambah bagangan tea). The tea samples were studied for their antioxidant and cytotoxic activities. pH of tea samples was measured. Proximate analyses including moisture, ash and protein content of the tea samples were also conducted. In a sensory evaluation, thirty participants were involved to assess several attributes (aroma, colour, taste, after-taste, astringency, overall acceptability) at 7- point hedonic scale. The findings found that S. palustris extracts showed more phytochemicals and have higher ABTS, TFdC, TFC values, whereas D. esculentum extracts have higher DPPH, FRAP, TPC and cytotoxicity values. As for the tea samples, the combination of pu-erh tea with both plant species (PTDESP) showed the highest DPPH value, while the combination of green tea with D. esculentum (GTDE) showed the highest ABTS and TPC values. pH of the herbal teas ranges from 5.5-6.6. Proximate analyses of the tea samples found the moisture content ranges from 11.6% -17.02%, ash content ranges from 1.16% 18.55% and protein content ranges from 0.35 mg/g DWB-1.277 mg/g DWB. Sensory evaluation of tea samples gave black tea with D. esculentum (BTDE) the highest overall score of 4.6 as the most acceptable. Although, none of the tea samples showed strong cytotoxicity, there is still some selectivity towards glucose-starved condition for mixture of sambah bagangan with both plant species (SBTDESP) and pu-erh tea with both plant species (PTDESP). Nonetheless, further studies including anticancer ability screening with wider variables are required to fully understand the potential of these two plant species.

Includes bibliographical references