- Title
- Bioactive compounds, antioxidant and cytotoxic capacities of two Vietnamese medicinal plants: Phyllanthus amarus and Paramignya trimera
- Creator
- Nguyen, Van Tang
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Phyllanthus amarus (P. amarus) is known as a traditional herbal plant, which has been used for the prevention and treatment of various chronic diseases such as hepatitis, diabetes and cancer, while Paramignya trimera (P. trimera) is a medicinal plant that has been used for the treatment of chronic ailments, particularly cancer and cancer-like diseases. To date, little research on the optimization of drying and extraction conditions for obtaining the highest phytochemical content and pharmacological capacity from the P. amarus and P. trimera has been reported. Therefore, the objectives of this research were to evaluate the effects of different drying methods, various extraction and drying conditions on the phytochemical yield, antioxidant and cytotoxic capacities of dried samples, extracts and fractions from the P. amarus and P. trimera plants. This was to identify an optimal drying method, extraction and drying conditions for the preparation of the dried samples, powdered extracts and fractions from the entire plant of P. amarus and root and leaf of P. trimera. The results indicated that the infrared drying at 30°C and microwave drying at 400 W were the optimal methods for obtaining the highest levels of bioactive compounds and antioxidant capacity from the P. amarus and the P. trimera, respectively. Water and methanol were the best solvents for the extraction of phenolic compounds and saponins as well as the retention of antioxidant potential from the P. amarus and the P. trimera, respectively. Microwave-assisted extraction parameters using water as a solvent at an extraction time of 30 min, an irradiation time of 14 s/min and a ratio of solvent to sample of 150 mL/g were the optimal conditions for withdrawing the phenolic compounds and retaining antioxidant activity from the P. amarus. The highest levels of saponins and antioxidant capacity were achieved by microwave-assisted extraction using 100% methanol as a solvent, an irradiation time of 4 s/min, an extraction time of 50 min and a solvent to sample ratio of 50 mL/g for the P. amarus, and at 100% methanol, an extraction time of 40 min and a solvent to sample ratio of 100 mL/g for the P. trimera. Twelve and eleven phytochemical compounds were identified in the ethanol extract from the P. amarus and in the methanol extract from P. trimera root, respectively. The methanol extracts from the P. trimera root and leaf displayed potent cytotoxic capacity on various cell lines including MiaPaCa-2 (pancreas), HT29 (colon), A2780 (ovarian), H460 (lung), A431 (skin), Du145 (prostate), BE2-C (neuroblastoma), MCF-7 (breast), MCF-10A (normal breast), and U87, SJ-G2, SMA (glioblastoma), with the GI50 values ranging from 15-32 μg/mL for the P. trimera root and 31-81 μg/mL for the P. trimera leaf. In particular, the cytotoxic potential on pancreatic cancer cells (MiaCaPa2, BxPc3, and CFPAC1) of methanol extracts from the P. trimera root and leaf (100-200 μg/mL) was significantly higher (p<0.05) than those of four fractions from the P. trimera root (50 μg/mL), ostruthin at 20 μg/mL (a major compound in P. trimera) and gemcitabine (50 nM), but being comparable to a saponin-enriched extract from quillajia bark at 200 μg/mL (a commercial product). Higher cytotoxic activity of methanol extract from the P. amarus on different cell lines (MiaPaCa-2, HT29, A2780, H460, A431, Du145, BE2-C, MCF-7, MCF-10A, U87, SJ-G2 and SMA) was observed in comparison to the water extract and the nine fractions of methanol extract from the P. amarus. However, the cytotoxic potential of methanol extract from the P. amarus (200 μg/mL) on MiaCaPa2 cells was significantly lower (p<0.05) than those of gemcitabine (50nM) and a saponin-enriched extract from quillajia bark (200 μg/mL), but to be significantly higher than that of Phyllanthin at 2 μg/mL (a major compound in P. amarus. The findings from this research allow us to conclude that both P. amarus and P. trimera are rich sources of bioactive compounds, which display great antioxidant and cytotoxic capacities in vitro. Therefore, the extracts and fractions from the P. amarus and P. trimera are promising lead sources for the potential development of natural antioxidant products and/or novel anticancer drugs, respectively.
- Subject
- Phyllanthus amarus; Paramignya trimera; medicinal plants; bioactive compounds; antioxidant capacity; cytotoxic capacity
- Identifier
- http://hdl.handle.net/1959.13/1383681
- Identifier
- uon:31973
- Rights
- Copyright 2018 Van Tang Nguyen
- Language
- eng
- Full Text
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