Antioxidant and Cytotoxic Activity of the Black Sea Cucumber (Holothuria atra) Body Wall Methanolic Extract through Multiple in vitro Assays: Its Possible Implication in Cancer Management

Abstract

INTRODUCTION

Even in recent times, there is still no known cure for cancer which is still one of the leading causes of morbidity around the world. A lot of interventions were made and a lot of natural anticancer agents are explored to end the preponderance of the disease. Still, a definite cure is not found. To solve the problem, the researchers evaluated in this study the antioxidant and cytotoxic activity of the sea cucumber (Holothuria atra) in which its medicinal value is attributed to the presence of bioactive agents with promising biological and pharmacological properties. The saponins and phenolics content were also determined qualitatively and quantitatively.

METHODS

The sea cucumbers were collected from the coast of Sagay, Negros Occidental and its body wall extract was obtained through methanolic extraction. Next, the bioactive components of the extract, specifically its saponin and phenolics content were determined through foam test, ferric chloride test, Folin-Ciocalteu and gravimetric method. Its antioxidant activity was tested through DPPH (diphenyl-2-picryl hydrazyl) and Hydrogen Peroxide (H2O2) Assays. Then, its cytotoxicity was tested to the brine shrimp nauplii, S. cerevisiae cells through Brine Shrimp Lethality Assay and Methylene Blue Reduction Assay, respectively. It was also tested to the mung beans through Seed Viability test using the following concentrations: 500 ppm, 1000 ppm, 2500 ppm and 5000 ppm.

RESULTS

The H. atra body wall methanolic extract scavenged 95.93% and 91.40% of DPPH and H2O2 radicals respectively. The extract also produced a dose dependent cytotoxicity effect to brine shrimp nauplii and yeast cells with an LC50 of 629.63 ppm and 274.07 ppm respectively. As mentioned by Meyer et al. (1982), LC50 value of less than 1000 μg/mL is toxic. Thus, it is considered to be toxic. Moreover, it inhibited the germination ofthe mung bean seeds as compared to the control group.

DISCUSSIONS

The cytotoxicity of the H. atra methanolic extract may be due to the presence of saponins (1.43%) and phenols (0.18 mg) which were obtained by phytochemical tests. Thus, the body wall methanolic extract of H. atra contains phenolic and saponins and exhibits antioxidant and cytotoxic activity which could be a promising source for anti-cancer drug breakthrough. Further in vitro studies were needed such as MTT assay, anti-metastatic assay using breast or colon carcinoma model may be evaluated to test its efficacy as potential anticancer agent.