Browsing by Author "Nadeeshani, R."

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Comparison of the basic nutritional characteristics of the first extract and second extract of coconut milk
(2015) Nadeeshani, R.; Wijayaratna, U.N.; Prasadani, W.C.; Ekanayake, S.; Seneviratne, K.N.; Jayathilaka, N.
Determination of polyphenol content in coconut milk by modified Folin-Denis assay
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Nadeeshani, R.; Seneviratne, K.N.; Jayathilaka, N.
Polyphenols are micronutrients which has nutritional value owing to their antioxidant activity. Polyphenol content is usually determined by the standard Folin-Denis Assay. Water soluble compounds commonly present in biological samples, such as proteins, ascorbic acid, DNA and RNA may interfere with this assay. Therefore, it is difficult to determine whether the antioxidant capacity of such samples are owing to these interfering compounds or other polyphenols present in the aqueous extracts (AE) like coconut milk (CM). In order to overcome these drawbacks, a modified extraction method was employed to remove proteins from the AE of CM to determine the polyphenol content in first (FE) and second (SE) extracts of both domestic and commercial preparations of CM using Folin-Denis assay. The results were reported as Gallic acid equivalents (mg/mL). Proteins/peptides present in the AE of CM (1.00 mL) was removed by organic extraction with chloroform (1.00 mL), distilled water (4.00 mL) and methanol (4.00 mL). Samples were mixed at 30 Hz for 01 min followed by centrifugation at 6000 rpm for 05 min. The methanolic layer was used for the Folin-Denis assay. The methanolic extracts (ME) were confirmed free of proteins by Bradford assay. Results showed significantly low polyphenol content in the ME compared to the AE indicating interference in the assay from proteins/peptides present in the AE of CM. Corresponding antioxidant activity of the ME of both FE and SE of domestic CM preparations were significantly higher compared to the commercial counterparts regardless of the presence of high polyphenol content in the AE. Therefore, the modified Folin-Denis assay reported here determine the polyphenol content in AE of food preparations that may contribute to their antioxidant potential.
A preliminary study of lip moisturizer rich in antioxidants produced using coffee leaf extract
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Gunasinghe, K.G.; Nadeeshani, R.; Jayathilaka, N.
As the body’s first environmental defense, the skin is exposed to various sources of free radical damage including the sun. In addition, to maintain healthy skin, it is important to maintain the moisture content not only in the deeper dermal and epidermal layers but also at the surface. As such, there are numerous skin moisturizers commercially available specially formulated to not only moisturize the body, face and the lips but also block the harmful rays from the sun to protect the skin surface. The composition of the lip moisturizers available in the market varies from brand to brand. These products often contain castor oil, carnauba wax and chemicals/ preservatives such as propyl paraben, methyl paraben, retinyl palmitate, tocopheryl acetate etc. as well as different agents to block the harmful rays from the sun. Antioxidants can be added to these products to neutralize the free radicals that can cause damage to the skin. Plant polyphenols are known to have high antioxidant activity. In this study, we have formulated a lip moisturizer with aqueous extracts from coffee leaves rich with polyphenols in an effort to develop a product that can neutralize free radical damage on the surface skin. The product was developed using bees wax, vaseline, coffee leaves and water (1: 2: 1: 11.5) with no other additional chemicals to formulate a natural healthy cosmetic. Polyphenols in the water extract was extracted in to methanol by removing the proteins using chloroform. The polyphenol content in the aqueous extract (0.18 ± 0.01 mg/ml) was measured by Folin-Denis assay as Gallic acid equivalent, using water as the control. The antioxidant activity of the extract was measured by DPPH radical scavenging assay. The percentage inhibition of DPPH radical scavenging activity of the aqueous extract of the coffee leaves measured using water as the blank gave 83.46 ± 0.11% of inhibition. Each sample was assayed three times for three biological replicates. The polyphenol content and the percentage inhibition of DPPH radical scavenging activity of the aqueous extracts, extracted from the formulated lip moisturizer were 0.14 ± 0.01 mg/ml and 83.44 ± 0.43% respectively. There is no statistically significant difference in the polyphenol content and the antioxidant activity between the aqueous extracts (p< 0.01). Lip moisturizer produced without the additon of coffee leaf extract was used as the control. According to the DPPH assay 99.97± 0.27% of percentage inhibition of DPPH radical scavenging activity was retained. Therefore, the lip moisturizer formulated with the coffee leaf extract retained the antioxidant properties.