| Summary: | 博士 === 國立臺灣科技大學 === 化學工程系 === 103 === One of the not well identified medicinal plants is sarang semut (Myrmecodia pendens) which might be a new source of therapeutic agents.Traditionally, folks usually use the huge swelling (known as tuber) part of sarang semut as herbal remedies. The efficacy of extracts of Sarang semut against different cancer cells was reported. The observed antioxidant activity and therapeutic effect of sarang semut extract was supposed to be due to antioxidant compounds contained in it.
The recovery of antioxidants was investigated using water bath extraction at 55oC from sarang semut. The effects of parameters such as extraction time, composition of solvent mixture and solvent to sample ratio were investigated at three levels for each and the optimum extracting parameters were: time, 4 h; solvent (ethanol/water; v/v), 80%; and solvent to sample ratio, 50 mL/g. Under these optimal conditions, a yield of 13.82% was obtained. The free radical scavenging activity (antioxidant activity) of the extract was evaluated using DPPH radical and the IC50 occurred at 96.21 ± 9.03 μg /mL of extract. The total phenol content (TPC) and total flavonoid content (TFC) were determined using the designed methods and found to be 330.61 ± 2.13 mg gallic acid equivalent/g dry extract and 63.28 ± 1.75 mg quercetin equivalent/g dry extract respectively. The extract obtained under optimum conditions was analyzed by HPLC and five flavonoid compounds are identified and their contents are (mg/g dry extract): kaempferol (13.767, luteoline (0.005), rutine (0.003), quercetin (0.030) and apigenin (4.700).
The crude extract (CE) obtained under optimum condition was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF) was selected for further analysis based on its antioxidant activity. Two major phenolic compounds (rosmarinic acid and procyanidin B1) were identified, confirmed and quantified using a combination of techniques LC/ESI/MS/MS, UV/Vis and HPLC. But confirmation and quantification of the third compound (oligomer of procyanidin B1) was hampered by lack of commercial standard. The concentration of rosmarinic acid and procyanidin B1 was found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively.
Reliable RP-HPLC/UV analytical method was developed for estimation of total phenolic and total flavonoid contents. Commercial gallic acid, ascorbic acid, quercetin and catechin were used as standards during method development. Total phenolic content (TPC) and total flavonoid content (TFC) were determined from methanol extracts of sarang semut using HPLC method. The HPLC method developed in this work was compared with the well-known spectrophotometric method by analyzing spiked samples. Parameters like standard deviation, mean value, percentage recovery and % relative standard deviation (%RSD) were used to compare the two methods. The accuracy (% recovery) of the new method varies from 90.82% to 101.34 % and %RSD was less than 1.0%. These values are within the range of % recovery and % RSD obtained by using spectrophotometric method (89.44 - 101.90 %recovery and 0.44 – 3.59 %RSD).
|
|---|
