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Isolation, characterisation and antioxidant activity of bioactive ingredients of cissus discolor blume
Author
Ma, Hnin Hnin Aung
Supervisor
Chia, Lian Sai
Abstract
The medicinal plants have been in use for many centuries and have provided reliability and effectiveness in treating and preventing diseases. The value of medicinal plants has also been endorsed by the World Health Organization. Thus, medicinal plants are an important source of inexpensive drugs for many people throughout the whole world.
One of the most remarkable features of medicinal plant research of the last decade is the enormously increasing interest being taken in the biological activities of flavonoids. Flavonoids belong to the recently popular phytochemicals (i.e. chemicals derived from plant material with potentially beneficial effects in human health). Flavonoids are water-soluble antioxidants in fruits, vegetables, tea and skin of tubers and roots. Many of the alleged effects of pharmacological doses of flavonoids are linked to their known functions as strong antioxidants, free radical scavengers, metal chelators and their interaction with enzymes, adenosine receptors, and biomembranes. Enormous research has proceeded to identify the compounds in fruits and vegetables that provide protection from disease-causing agents. In plants, flavonoids appear to act as a natural sunscreen, protecting against ultraviolet damage. In people, flavonoids appear to interfere with the complex of processes that lead to chronic diseases such as cancer, heart disease, and other degenerative diseases associated with ageing. Therefore, the emphasis in the area of medicinal plant has gradually been focused on finding out effective antioxidant activity from plants and extracting them if possible.
Since antioxidant activity is dependent on the flavonoids and flavonoids are water-soluble compounds, it is possible to find out plants with high antioxidant activities by ultraviolet (UV) spectroscopic method and electron spin resonance (ESR) spin trapping technique using plant extracts. Consequently, the initial part of this study was focused on screening work. The 2D chromatographic data show that the medicinal plant cissus discolor blume (CD) contains anthocyanins, methylated flavone, isoflavone and stilbene. After isolation and HPLC separation, the spectra show that CD contains methylated flavone of quercetin. The non-polar solvent extract (lipid phase system) of CD has less antioxidant activity, while the polar solvent extracts (aqueous phase system) of ethyl acetate, methanol and 1% methanolic HCI have higher antioxidant activities than the other extracts. Among these extracts, ethyl acetate extract has the highest antioxidant activity. The experimental results show that the antioxidant activities of ethyl acetate and methanol extracts are same as that of standard quercetin and higher than those of standard rutin and vitamin C. The stilbene compounds in CD have higher antioxidant activity than the quercetin. The results also show that the findings from the UV method are quite consistent with those from the ESR method.
Chapter one of this report introduces the active substances of medicinal plants and antioxidant activities of flavonoids. Chapter two outlines free radical generation and antioxidant defense system in our body. Chapter three introduces the phenomena of electron spin resonance. Then, analytical methods used to determine the antioxidant ablility by UV and ESR methods are discussed in chapter four. A lot of data achieved by screening work and time-consuming experiments are listed in chapter five. These data mainly concern the antioxidant activities in different extracts and fractions of the medicinal plant CD. Chapter six summaries the major findings of this study and recommend some possible areas for further research.
One of the most remarkable features of medicinal plant research of the last decade is the enormously increasing interest being taken in the biological activities of flavonoids. Flavonoids belong to the recently popular phytochemicals (i.e. chemicals derived from plant material with potentially beneficial effects in human health). Flavonoids are water-soluble antioxidants in fruits, vegetables, tea and skin of tubers and roots. Many of the alleged effects of pharmacological doses of flavonoids are linked to their known functions as strong antioxidants, free radical scavengers, metal chelators and their interaction with enzymes, adenosine receptors, and biomembranes. Enormous research has proceeded to identify the compounds in fruits and vegetables that provide protection from disease-causing agents. In plants, flavonoids appear to act as a natural sunscreen, protecting against ultraviolet damage. In people, flavonoids appear to interfere with the complex of processes that lead to chronic diseases such as cancer, heart disease, and other degenerative diseases associated with ageing. Therefore, the emphasis in the area of medicinal plant has gradually been focused on finding out effective antioxidant activity from plants and extracting them if possible.
Since antioxidant activity is dependent on the flavonoids and flavonoids are water-soluble compounds, it is possible to find out plants with high antioxidant activities by ultraviolet (UV) spectroscopic method and electron spin resonance (ESR) spin trapping technique using plant extracts. Consequently, the initial part of this study was focused on screening work. The 2D chromatographic data show that the medicinal plant cissus discolor blume (CD) contains anthocyanins, methylated flavone, isoflavone and stilbene. After isolation and HPLC separation, the spectra show that CD contains methylated flavone of quercetin. The non-polar solvent extract (lipid phase system) of CD has less antioxidant activity, while the polar solvent extracts (aqueous phase system) of ethyl acetate, methanol and 1% methanolic HCI have higher antioxidant activities than the other extracts. Among these extracts, ethyl acetate extract has the highest antioxidant activity. The experimental results show that the antioxidant activities of ethyl acetate and methanol extracts are same as that of standard quercetin and higher than those of standard rutin and vitamin C. The stilbene compounds in CD have higher antioxidant activity than the quercetin. The results also show that the findings from the UV method are quite consistent with those from the ESR method.
Chapter one of this report introduces the active substances of medicinal plants and antioxidant activities of flavonoids. Chapter two outlines free radical generation and antioxidant defense system in our body. Chapter three introduces the phenomena of electron spin resonance. Then, analytical methods used to determine the antioxidant ablility by UV and ESR methods are discussed in chapter four. A lot of data achieved by screening work and time-consuming experiments are listed in chapter five. These data mainly concern the antioxidant activities in different extracts and fractions of the medicinal plant CD. Chapter six summaries the major findings of this study and recommend some possible areas for further research.
Date Issued
2000
Call Number
QK99 Ma
Date Submitted
2000