Rs Chapter 2.docx

CHAPTER 2 REVIEW OF RELATED LITERATURE AND STUDIES

This chapter discusses the review of relate literature and studies cited on the antibacterial activity of the A. carambola leaves.

Related Literature Star Fruit Description Averrhoa carambola is a species of tree in the family Oxalidaceae; it has a number of common names, including carambola and starfruit. Starfruit is believed to have originated in Ceylon and the Maluccas, but it has been cultivated in the Southeast Asia and Malaysia for hundreds of years (Dasgupta, 2013). It is known for its unique star shape and rich golden color. The fruit was found to be oblong in shape, in average, being 7.92 cm long and 5.24 cm in width (Narain, 2001). Leaves of the said plant are 15-25 cm long, alternate, spirally arranged, ovate to ovate-oblong in shape, imparipinnate, shortly petiolate with 5-11 green pedant leaflets of 2-9 cm long and 1-4.5 cm wide (Dasgupta, 2013). A starfruit tree is usually small or medium in height (22 to 33 ft.; 7 to 10 m), spreading 20 to 25 ft. in diameter; 6 to 7.6 m, evergreen, and single or multi-trunked. It can adapt well in different types of soils. But these grow best where the soil reaction is moderately acid to neutral pH. (Crane, 2001).

Star Fruit Uses

Taxonomic Hierarchy

Kingdom: Plantae Subkingdom: Tracheobionta Superdivision: Spermatophyta Division: Magnoliophyta Class: Magnoliopsida Subclass: Rosidae Order: Geraniales Family: Oxalidaceae Genus: Averrhoa L. Species: Averrhoa carambola L.

Health Benefits of Star Fruit

Related Studies Antibacterial Activity of Star Fruit A comprehensive study conducted on the phytochemical and antibacterial activity of the petroleum ether extract of Averrhoa carambola leaves. The researchers conducted phytochemical screening which showed the presence of flavonoid, carbohydrate, glycoside and steroid. In testing the antibacterial

property of the extract, among the ten test subjects, it is confirmed that the extract showed large inhibition in Salmonella typhi, Pseudomonas aeruginosia, Escherichia coli, and Bacillus megaterium, which indicates the antibacterial activity of the extracts against these bacteria (Das, J. et al., 2013). The study conducted by Das, B.N., and Ahmed, M. in 2012, with ethanolic fruit extract of Averrhoa carambola for its antibacterial and cytotoxic activities. Disk diffusion method was used in antibacterial activity evaluation and for cytotoxic activity; brine shrimp lethality bioassay was performed to estimate LC50 values. The water extract of the A. carambola performed significant antibacterial activity against

Staphylococcus aureus and Bacillus cereus while the

dichloromethane extract also showed antibacterial activity against Escherichia coli and Salmonella typhi. The dichloromethane soluble partitionate showed strong cytotoxicity against the brine shrimp, Artemia salina with an LC50 of 1.180 µg/mL. M.A. Mustafa, et al. (2014) have studied the extracts of freshly harvested dragon fruit, starfruit and mangosteen and were assessed against the pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The researchers extracted different fractions from the edible fruit portions using hexane, methanol, acetone and ethyl acetate and were assessed for antimicrobial activity. It was detected that the A. carambola ethanolic extract and acetone extracts at a concentration as low as 20 ppm have has antimicrobial activity. It also showed the highest phenolic content on the methanolic extract of A. Carambola.

The plant extract of A. carambola showed moderate level of growth inhibition

against

Streptococcus

agalactiae,

Streptococcus

pyogens,

Pseudomonas spp. And Staphylococcus saprophyticus whereas potent inhibition activity against Shigella dysenteriae (zone of inhibition 9 mm at 500 mg/kg body weight compared to standard drug kanamycin (zone of inhibition 10 mm at 30 µg/disc) (Hossain, T., et al., 2017). Research findings of Ariharan, et. al., that fruit juice of A. carambola star fruit has vitamin C content of 16.26 mg/g. Antibacterial activity were carried out in order to ascertain the disease resistance property of the fruit juice and it showed that the gram positive has 70% inhibition and the gram negative bacteria has 65% inhibition efficiency.

Antifungal Activity of Star Fruit A study in antimicrobial activity of 3 different solvent extracts (Aqueous, Ethyl Acetate and Petroleum ether) of A. carambola leaves primarily its antifungal property was conducted against pathogenic Fungi and Yeast using agar well diffusion method. It can be concluded that the above The Ethyl Acetate extract of Averrhoa carambola was found to be most effective antifungal activity against Mucor hiemalis, Alternaria alternate, Fusarium eumartii, Candida albicans and Sacchromyces cerevisiae (Mewara, D., Tamakuwala, H. and Desai, B., 2017).

Methods in Evaluating Antimicrobial Activity A study conducted by Das, B. N., and Ahmed, M. of the antimicrobial and cytotoxic activity of the methanolic extract of Averrhoa carambola. Disk diffusion technique was used to evaluate the antimicrobial activity of A. carambola with various gram-positive and gram-negative bacteria. Clinical and Laboratory Standards Institute or CLSI published an accepted and approved standards for Disk diffusion technique for bacteria and yeast testing (Balouiri M., Sadiki M., Ibnsouda S. K., 2016). Another study conducted once again by Dimpal Mewara, Honey Tamakuwala, and Dr. Binita Desai of the antifungal activity of A. carambola leaf extract. In testing its antifungal activity, agar well assay technique was used. Agar well method is technique that is widely used in antimicrobial activity of plants or microbial extracts. It is similar to Disk-diffusion method but the difference is; a hole is punched (6 to 8mm) in the agar plate in which the extract is induced into the well (Balouiri M., Sadiki M. and Ibnsouda S. K., 2016).