| Summary: | 碩士 === 國立屏東科技大學 === 農園生產系所 === 98 === Pinus morrisonicola Hayata is an indigenous pinaceae species in Taiwan. At prensent, it was widely cultivated in central region of Taiwan and saplings were potted often. Its leaves can be used for wine and healthy soft drinks making. In the recent years, many reports revealed that pine needles had biological activity and rich nutrition. The antioxidative compounds including polyphenols, anthocyanins, and flavonoids were found in P. morrisonicola Hay.The objective of this study was to evaluate the variations of antioxidative abilities and changes of phenolics of P. morrisonicola Hay. needles in accord with different extraction methods, growth seasons, drying treatments, and steeped methods. There were three sessions in this study. The first was to evaluate the effects of different extraction methods on antioxidative abilities. The second was to evaluate the effects of different growth seasons and drying treatments on antioxidative abilities. The third was to evaluate the effects of different steeped methods and time on antioxidative abilities.In the first session, when the P. morrisonicola Hay. needles were
oven-dried and lyophilized, it were subjected to extracted using six solvents namely distilled water, 100 % ethyl acetate, 100 % methanol, 50 % methanol, 95 % ethanol and 50 % ethanol. Then, the antioxidant compound contents and antioxidative abilities were investigated. Moreover, samples were extracted using soxhlet and ultrasonic extraction separately and the antioxidant compound contents and antioxidative abilities were investigated. Among the six different extraction solvents, 50 % methanol was the best extraction solvent and the extracts had higher contents of total phenols, total flavonoids, and DPPH scavenging ability. 100 % Ethyl acetate had higher trolox equivalent antioxidant capacity (TEAC). In lyophilization, 50% methanol extract had highest inhibition of angiotensin converting enzyme (ACE) activity. In oven-drying, ethanol had highest ACE inhibitory ability. Among different extraction methods, the soxhlet extraction had highest content of antioxidant contents and antioxidative ability.
The second session was to investigate antioxidant content and antioxidative abilities of the P. morrisonicola Hay. needles harvested in different seasons namely spring, summer, autumn, and winter, and when they were after oven-drying and lyophilization. This session demonstrated that the contents of chlorophyll in the winter needles were significantly higher than that in other seasons. The summer needles had significantly higher chlorophyll a/b ratio, contents of total phenols, total flavonoids, DPPH scavenging, reducing power, total antioxidant activities, ferrous metal chelating, superoxide anion scavenging, TEAC, contents of epicatechin, and p-coumaric acid. The spring needles had significantly higher ACE inhibitory activity. As to different drying treatments, lyophilization treatment had significantly higher antioxidative abilities than oven-drying.The third session was to investigate antioxidant content and antioxidative abilities of the oven-drying and lyophilization treated P. morrisonicola Hay. needles using hot-steeped and cold-steeped with steeped time for 15min, 1 hour, 3 hour, and 8 hour respectively. Results showed that lyophilization treated needles in hot-steeped had significantly higher chlorophyll, flavonoids contents and TEAC. The hot-steeped oven-drying treated needles had significantly higher total phenolics content in all steeping time and all different steeping methods, except when they were steeped for one hour. The lyophilization treated needles had significantly higher DPPH scavenging when they were hot-steeped for one and eight hours.The extracts of P. morrisonicola Hay. needles contain higher amount of total phenolic content and it may probably be the reason why they had higher antioxidant activity. Meanwhile, the phenolic compounds contents and antioxidative activities of needles can be varied according to extraction methods, drying treatment, growing season, and steeping methods. The results of this study can be provided as a reference for the utilization and the application on health foods, and can improve the economic values of Pinus morrisonicola Hay. needles in the future.
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