Evaluation of Antihyperglycaemic and Antimicrobial Effects of Different Extracts (Methanol, Ethanol, Chloroform and Aqueous) of Andrographis paniculata and Andrographis paniculata Herbal Tea

Gan, Jia Yi (2020) Evaluation of Antihyperglycaemic and Antimicrobial Effects of Different Extracts (Methanol, Ethanol, Chloroform and Aqueous) of Andrographis paniculata and Andrographis paniculata Herbal Tea. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Andrographis paniculata has long been used as a medicinal herb to treat various health conditions such as diabetes, fever, cold and diarrhoea. Andrographolide is the major diterpenoid found in Andrographis paniculata. This bioactive compound contributes to the biological effects of the plant, for instance, antihyperglycaemic, antimicrobial and antioxidant activities. In this project, different extracts of A. paniculata were tested for α-glucosidase inhibition activity and antimicrobial activity. A. paniculata herbal tea was also tested to compare the activities of herbal tea to solvent extracts of A. paniculata. The different solvent extracts of A. paniculata as well as A. paniculata herbal tea were first prepared and then analysed using High Performance Liquid Chromatography (HPLC) to determine the presence of andrographolide in the samples. The result showed that the retention time of andrographolide peak was at 4.964 min. This peak was found to be present in methanol extract at 4.95 min, ethanol extract at 4.946 min and chloroform extract at 4.949 min. However, it was absent in aqueous extract and herbal tea. This indicated methanol, ethanol and chloroform extracts of A. paniculata consisting of andrographolide while aqueous extract and herbal tea did not contain andrographolide, proving that andrographolide is insoluble in water, however, soluble in polar organic solvents. In α-glucosidase inhibition assay, the IC50 values were 1.14±0.33 mg/mL, 1.17±0.25 mg/mL, 0.74±0.14 mg/mL and 2.07±0.37 mg/mL for methanol, ethanol, chloroform and aqueous extracts, respectively. The polar organic extracts of A. paniculata were able to inhibit Staphylococcus aureus at the concentration of 45, 60, 75 and 90 mg/mL. The inhibition zones were 7.67±0.33 mm, 7.67±0.33 mm and 8.33±0.33 mm for methanol, ethanol and chloroform extracts of A. paniculata, respectively at 90 mg/mL concentration. Thus, it is proven that polar solvent extracts of A. paniculata exhibit antimicrobial activity and are able to inhibit α-glucosidase activity. The reason why the aqueous extract of A. paniculata did not possess antimicrobial property and A. paniculata herbal tea was unable to inhibit both α-glucosidase activity and microbial growth, was due to the absence of andrographolide. Therefore, andrographolide in polar organic extracts of A. paniculata contributes to the antihyperglycaemic and antimicrobial properties of A. paniculata.