臺灣銀膠菊植物之生物活性探討

Abstract

銀膠菊(Parthenium hysterophorus L.)係菊科草本植物，此種植物是台灣新歸化的有毒雜草，在台灣南部已呈歸化現象，目前已擴及至台中縣梧棲、大度一帶，且其族群有日益增多之趨勢。根據野外的觀察，發現此植物之所以形成優勢雜草，除了與該植物之多產性、侵略性有關外，植物相剋作用可能亦扮演著重要的角色。 銀膠菊植物中所含的酚酸化合物有chlorogenic acid、2,6-dihydroxybenzoic acid、3,4-dihydroxycinnamic acid、3,4-dimethoxyphenylacetic acid、2-hydroxybenzoic acid、4-hydroxybenzoic acid、L-4-hydroxy-3-methoxymandelic acid及3-methoxyphenylacetic acid。此外，銀膠菊植物亦含有多種的sesquiterpene lactone化合物；主要有parthenin，它會抑制人類纖維原細胞(Human fibroblasts，HFW)和中國倉鼠卵巢細胞(Chinese hamster ovary，CHO)的生長，當其以0.2ppm的濃度處理時，HFW可達50％的抑制程度；而CHO則可達23％的抑制程度。 將銀膠菊植株細分成根、莖、葉、花序四部份，分別配製成1％、2％、3％、4％、5％(W/V)的水溶萃取液，對蕃茄種子進行生物分析以比較其植物毒性程度，結果顯示根、莖、葉、花序之水溶萃取液在1％時分別抑制蕃茄根生長達29.6％、40.3％、50.1％及42.5％；以葉的水溶萃取液抑制程度最強，其次依序?花序、莖和根；而在另外四種濃度的萃取液中亦有此趨勢，由此顯示銀膠菊植物的毒性物質存在於葉及花序兩部份甚於莖和根兩部份。 以SDS-PAGE電泳分析蕃茄種子之總蛋白質量，結果顯示蕃茄種子之總蛋白質量會因銀膠菊萃取液的處理，有些蛋白質帶的蛋白質合成量會增加，有些則減少。

Parthenium hysterophorus L., a compositae, is a new naturalized toxic weed in southern Taiwan and is now widely dispersed in WuChi and Dahduh, Taichung County. According to field observations, it was found that the allelopathic effect may have an important role. Because of the aggressive nature of this weed and serious dermatological effect on human health, a series of studies, isolation, and purification of secondary metabolites, using chromatography, bioassays, scanning electron microscopy and SDS - PAGE electrophoresis, were conducted to elucidate the structure and biological activity of the secondary metabolites found in the plant. Results of paper chromatography and high performance liquid chromatography analyses showed that extracts of Parthenium hysterophorus, L. contains the following phenolic acids, chlorogenic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxycinnamic acid, 3, 4-dimethoxyphenylacetic acid, 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, L-4-hydroxy-3-methoxymandelic acid and 3-methoxyphenylacetic acid. In addition to the phenolic compounds, some sesquiterpene lactones were found by using thin layer chromatography and identified by mass spectrometry. Parthenin was identified to be one of the major component in sesquiterpene lactones. Parthenin inhibits the growth of human fibroblast cells (HFW) and chinese hamster ovary cells (CHO) at concentrations of 0.2 ppm, where CHO cells growth were inhibited by 23% and HFW cells growth were inhibited by 50%. In order to understand what roles the trichomes might have in P. hysterophorus L. plants, the scanning electron microscope was used to observe where the trichomes on leaf surfaces. The trichomes on leaves were collected and their secondary metabolites were extracted for analysis. It was discovered that there were large amounts of sesquiterpene lactones in these tissues. A series of aqueous extracts, 1%, 2%, 3%, 4% & 5% (w/v) were made from the root, stem, leaf, and inflorescence of the plants. Tomato seeds were used to determine phytotoxicities of P. hysterophorus L. The results of bioassay clearly showed that the 1% extract of root, stem, leaf and inflorescence significantly inhibits 29.6%, 40.3%, 50.1% & 42.5% of the growth of tomato radicle respectively. The inhibition was the highest in leaf extract followed by extracts of inflorescence, stem and root. The same pattern of inhibition was found in the other four extract concentrations. Further study on the mechanism of inhibition on radicle growth, we use SDS-PAGE electrophoresis to analyze the total amount of protein in tomato seeds pre-treated with P. hysterophorus L. extract. The total amount of protein in tomato seeds were increased and decreased depending upon the concentration of extracts.