Chemical composition, antioxidant activity and antibacterial mechanism of action from Marsilea minuta leaf hexane: methanol extract

BACKGROUND

In the present study, hexane: methanol (50:50) leaf extract of Marisela minuta has been evaluated for its chemical composition, antioxidant effect and the antimicrobial mechanism of action against food borne pathogenic bacteria.

RESULTS

The phytochemical evaluation of extract by GC/MS revealed the major abundance of benzoic acid-4-ethoxyethyl ester (43.39%) and farnesol acetate (18.42%). The extract exhibited potential antioxidant and free radical scavenging properties with promising antibacterial activities against the test pathogens with Pseudomonas aeruginosa being the most susceptible with maximum inhibition zone (17 mm) and IC50 value of 125 µg, respectively. The significant (p < 0.05) increase in intracellular super oxide dismutase (SOD), protein leakage, extracellular alkaline phosphatase and lactate dehydrogenase in treated test pathogens suggested an increase in oxidative stress reveling the mechanism of action of phytochemicals. Scanning electron microscopy analysis of treated pathogens also showed swollen and distorted cells. The bioactive molecules in the extract were efficiently docked with virulent enzymes and farnesol acetate showed best energy value of - 5.19 and - 4.27 kcal/mol towards Topoisomerase IV and SHV-2 respectively. Benzoic acid-4-ethoxyethyl ester showed best binding against TEM-72 with low binding energy value of - 4.35 kcal/mol.

CONCLUSION

Due to its antioxidant and antibacterial properties, the leaf extract of M. minuta may act as promising natural additives to prevent food spoilage bacteria.

Mitigating arsenic contamination in rice plants with an aquatic fern, Marsilea minuta

Dangers of arsenic contamination are well known in human civilization. The threat increases when arsenic is accumulated in food and livestock through irrigated crops or animal food. Hence, it is important to mitigate the effects of arsenic as much as possible. This paper discusses a process for reducing the level of arsenic in different parts of rice plants with an aquatic fern, Marsilea minuta L. A pot experiment was done to study the possibility of using Marsilea minuta as a phytoremediator of arsenic. Rice and Marsilea minuta were allowed to grow together in soils. As a control, Marsilea minuta was also cultured alone in the presence and absence of arsenic (applied at 1 mg/L as irrigation water). We did not find any significant change in the growth of rice due to the association of Marsilea minuta, though it showed a reduction of approximately 58.64% arsenic accumulation in the roots of rice grown with the association of fern compared to that grown without fern. We measured a bioaccumulation factor (BF) of > 5.34, indicating that Marsilea minuta could be a good phytoremediator of arsenic in rice fields.

Antitussive, expectorant activity of Marsilea minuta L., an Indian vegetable

Marsilea minuta L., an aquatic or sub-aquatic fern used as a vegetable, has wide applications in traditional/folk medicine in India and Bangladesh. In our study, we evaluated the antitussive, expectorant activity of M. minuta crude extracts. The antitussive activity of M. minuta methanol, ethyl acetate, and petroleum ether extracts was evaluated using ammonia and sulfur dioxide induced mice coughing. The expectorant activity was evaluated by the volume of phenol red in mice's tracheas. Extracts significantly increased mice's cough latent period and inhibited the frequency of cough induced by ammonia and sulfur dioxide, and improved tracheal phenol red output in expectorant evaluation. Methanol extract produced the highest activity in all tested models. Methanol extract at 500 mg/kg showed 59.5% and 55.8% inhibition in the number of coughing induced by ammonium liquor and SO₂, respectively, while it showed 89.3% increase in phenol red secretion at the same dose, which showed superior activity compared to other extracts. The present study provided evidence for M. minuta to be used as an antitussive and expectorant in Indian folk medicine.