Chemical Composition and Bioactive Properties of Sargassum aquifolium (Turner) C. Agardh and Its Potential for Pharmaceutical Application

Abstract

Seaweeds are known sources of marine bioactive substances with diverse biological activities important in the synthesis of medically important novel drugs. The proximate and elemental compositions as well as bioactive properties of a brown macroalga, Sargassum aquifolium (Turner) C. Agardh, were studied. Results showed that proximate composition of S. aquifolium contain high carbohydrate (32.29 ± 0.17%) and ash (30.19 ± 0.14%) content. Elemental composition of the seaweed exhibited a decreasing order of Na > Ca > K > Mg > Mn > Fe > Zn > Cu > Pb > Cr > Cd. The seaweed had a total phenolic content (TPC) of 5.74 ± 0.04 mg GAE/g. Antioxidant activities of S. aquifolium were characterized by having potent ABTS+ [2,2’-azino-bis (3-ethylbenzothiazoline- 6-sulfonic acid)] scavenging activity and high copper reduction capacity with IC50 value of 107 μg/mL and 21.01 μg/mL respectively. Evaluation of tyrosinase and elastase inhibition activities showed that S. aquifolium extract has potent inhibition activities with IC50 of 39.00 μg/mL and IC50 of 231.00 μg/mL, respectively – more effective than kojic acid and tocopherol. In addition, in vitro assessment of α-glucosidase and α-amylase inhibition property showed that S. aquifolium extract has potent inhibitory activity as compared to acarbose (standard anti-diabetic drug) with IC50 of 15.60 and 59.0 μg/mL, respectively. Also, the S. aquifolium extract exhibited effective antimicrobial activities against bacterial pathogens such as penicillin acylase-producing Bacillus cereus (MIC = 125 μg/mL), Staphylococcus saprophyticus (MIC = 250 μg/mL), methicillin-resistant Staphylococcus aureus (MRSA) (MIC = 250 μg/mL), Staphylococcus epidermidis (MIC = 250 μg/ mL), and Pseudomonas aeruginosa (MIC = 500 μg/mL). The current investigation is a pioneering study in the Philippines that shows the potential of S. aquifolium as novel source of bioactive compounds with important use for pharmaceutical applications.