Antioxidant, Antimicrobial and Cytotoxic Evaluation of Crude Curcumin Extract from Curcuma Longa (Turmeric) and Crude Aloe Vera Gel from Aloe Vera Leaves

Low, Hui Ching (2020) Antioxidant, Antimicrobial and Cytotoxic Evaluation of Crude Curcumin Extract from Curcuma Longa (Turmeric) and Crude Aloe Vera Gel from Aloe Vera Leaves. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

In recent years, the skincare industry has been flourishing as the concern regarding aging of skin has been growing among the public. Currently interests in curcumin as well as Aloe vera gel have been trending as more people share their self-made anti-aging skincare recipes involving these two compounds in social media. This project aims to extract and determine the antioxidant as well as the antimicrobial activities of curcumin and aloe gel and to review the cytotoxic effect of the curcumin and aloe gel towards mammalian cells. Crude curcumin was extracted using aqueous extraction and ethanolic extraction methods and validation of the extracted compound was performed through UV-Vis spectrophotometry. The yield of the aqueous extract was 8.13 ± 0.06% while the ethanolic extract yielded 9.32 ± 1.18% and the absorption spectrum of the samples peaked at 265nm for the former and 425nm for the latter. The antioxidant capacity of the samples was tested through DPPH assay and FRAP assay. The IC50 values were 18.92μg/mL for aqueous extract, 10.46μg/mL for ethanolic extract and 50.17% for aloe gel while the FRAP values were 0.22mM for both curcumin extracts and 0.30mM for aloe gel. The antimicrobial activity of the samples was evaluated through the Kirby-Bauer disc diffusion method using ampicillin as the positive control and distilled water as the negative control. All of the samples did not exhibit antibacterial activity against Escherichia coli, Staphylococcus aureus or Klebsiella pneumoniae and ampicillin was ineffective against K. pneumoniae. The cytotoxic evaluation was to be carried out in vitro against spontaneously immortalised human keratinocyte cells (HaCat) through microculture tetrazolium (MTT) assay. However, no experimental results were obtained, thus from review, it was determined that neither curcumin nor aloe gel are toxic towards humans. In conclusion, the extracted compounds have the potential to be applied as active ingredients in anti-aging skincare product formulation due to the antioxidant activities without adverse effect towards human.