Swagat Kumar Das

Free radical scavenging and antioxidant potential of mangrove plants: a review

Free radicals derived from reactive oxygen species and reactive nitrogen species are generated in our body by normal cellular metabolism which is enhanced under stress conditions. The most vulnerable biological targets of free radicals are cell structures including proteins, lipids and nucleic acids. Since antioxidants synthesized in the body are not sufficient under oxidative stress, their exogenous supply is important to prevent the body from free radical-induced injury. Recent researches have shown that antioxidants of plant origin with free radical scavenging property could have great importance as therapeutic agents in management of oxidative stress. Mangrove plants growing in inhospitable environment of the intertidal regions of land and sea in tropics and sub-tropics are equipped with very efficient free radical scavenging system to withstand the variety of stress conditions. These mangrove plants possess variety of phytochemical and are rich in phenolic compounds such as flavonoids, isoflavones, flavones, anthocyanins, coumarins, lignans, catechins, isocatechins, etc., which served as source of antioxidants. Isolation and identification of these antioxidant compounds offer great potential for their pharmaceutical exploitations. However, no comprehensive literature is available on antioxidants’ studies in mangrove plants in particular. Hence, the present review discusses the antioxidant potential of mangrove plants with its specific role under salt stress as well as the progress made so far in evaluation of antioxidant activities of different mangrove species.

Phytochemical profiling and bioactivity of a mangrove plant, Sonneratia apetala, from Odisha Coast of India.

ObjectiveTo test the antioxidant, antidiabetic, anticancer and antibacterial activities along with phytochemicals of Sonneratia apetala Buch.-Ham.MethodsThe antibacterial activity was determined by agar well diffusion method. The antioxidant activity was determined by standard assay. The antidiabetic activity was evaluated by α-glucosidase inhibition assay and in vivo anticancer property was determined against Ehrlich ascites carcinoma (EAC) cells in Swiss Albino mice. Further partial characterization of the methanol extracts was carried out by thin layer chromatography, high performance liquid chromatography, 1H nuclear magnetic resonance spectroscopy and Fourier transform-infra red spectrum spectral analysis.ResultsFour solvent extracts (acetone, ethanol, methanol and aqueous) of leaf and bark possess strong antioxidant properties. In vivo anticancer activity of methanol extract leaf indicated positive activity showing 34% inhibition against EAC cells in Swiss Albino mice. All extracts exhibited α-glucosidase inhibitory activity in a dose-dependent manner indicating presence of promising antidiabetic properties. The extracts possess strong antibacterial activity against the selected pathogenic bacteria (minimal inhibitory concentration ranging from 1.25–5.00 mg/mL). The partial characterization of the methanol extracts of leaf and bark revealed the presence of phenolics as the lead compound responsible for studied bioactivities of the plant extracts.ConclusionSonneratia apetala extracts have potent antibacterial, antioxidant, antidiabetic and anticancer properties which can be further exploited for its pharmaceutical applications.

The genus Avicennia, a pioneer group of dominant mangrove plant species with potential medicinal values: a review

ABSTRACT The genus Avicennia comprises eight species of mangrove trees that occur in intertidal zones of estuaries and seabeds found in tropical and temperate regions spanning throughout the world. The plants belonging to the genus have both ecological and economic benefits. Different parts of the plants have ethnomedicinal applications for treatment of various diseases such as cancer, diabetes, malaria, rheumatism, asthma, small pox and ulcer. Pharmacological investigations have revealed antimicrobial, antioxidant, anticancer, antidiabetic, anti-inflammatory activities and so on in these plants. The genus possesses some unique metabolites of varied chemicals classes, which are responsible for their wide range of pharmacological activities. The presence of different bioactive compounds such as alkaloids, flavonoids, phenols, saponins, tannins, glycosides and terpenoids has been detected. Hence, there is a great scope to discover new biological active phytochemicals from different mangrove species of genus Avicennia. Although many research articles have been published on various pharmacological aspects of different plants of the genus, no comprehensive review is yet available pertaining to their ethnomedicinal uses, chemical constituents and pharmacological activities. The present article discusses the diversity as well as distribution of different species of genus Avicennia along with an in-depth coverage of their ethnomedicinal uses, phytochemical and pharmacological profiles.

Ethnomedicinal, Antimicrobial and Antidiarrhoeal Studies on the Mangrove Plants of the Genus Xylocarpus: A Mini Review

Mangroves being stress tolerant plants possess unique metabolites with significant amount of bioactive compounds which could be isolated and evaluated for possible drug development with suitable biotechnology tools. The mangrove genus Xylocarpus comprises of four species viz. Xylocarpus granatum (Koenig), X. moluccensis (lamk.) and X. mekongensis Pierre and X. rumphii. However, X. rumphii is a less abundant mangrove plant. There have been reports that different species of Xylocarpus are used ethnomedicinallly for treatment of various diseases such as fever, malaria, cholera, diarrhoea, swelling of breast, elephantiasis, inflammation, dyslipidemia, pain, hyperglycaemia etc. Recent studies revealed that the extracts from different parts of the plant such as leaves, stem, bark and fruits possess phytoconstituents like alkaloids, glycosides, steroids, limnoids, terpenoids, flavonoids, tannins and other phenolics. Further, it has been established that the different solvent extracts of the plants have exhibited antimicrobial and antidiarrhoeal activities against a number of human pathogens which could be correlated to their phytoconstituents such as flavonoids, alkaloids, limnoids, tannins etc. The present study is aimed at compiling information on phytochemical, pharmacological and ethnomedicinal properties of mangrove plants of genus Xylocarpus, with a view to critically assess the legitimacy of the use of these plants for antimicrobial and antidiarrhoeal activities as well as providing directions for further research.

Antidiabetic potential of mangrove plants: a review

Diabetes mellitus is a heterogeneous group of metabolic disorders characterized by persistent hyperglycaemia and becoming a serious threat to mankind health in all parts of the world. Production of reactive oxygen species and disturbed capacity of antioxidant defence have been reported for enhanced production of free radicals in diabetic subjects. As oxidative stress is found to be a central event in the development of diabetic complications, hence antioxidants may play an important role in the improvement of diabetes and its associated complications. Currently there has been an increased interest globally to identify antioxidant compounds that are pharmacologically potent and have low or no side effects. Phytochemicals and metabolites from mangrove plants are reported to exhibit strong antioxidant properties in terms of both enzymatic and non-enzymatic activities. Recent researches have also revealed that a number of mangrove plants have shown antidiabetic activities attributed to their unique metabolites such as flavonoids, triterpenoids, limonoids and polysaccharides. Thus, mangrove plants can be of great use in tackling diabetic and its associated oxidative stress mediated complications. The present review highlights a relation between oxidative stress and diabetes and the role of mangrove plants in alleviating diabetes, in general, and oxidative stress mediated diabetic complications, in particular.

Pharmacological Applications of Metabolites of Mangrove Endophytes: A Review

The mangroves represent one of the most productive ecosystems located in the transition zone between land and sea characterized by periodic flooding and high salinity that confers unique environmental conditions to this biome. This ecosystem is dominated particularly by mangrove plant species that provide a unique environment harbouring diverse groups of microorganisms, including the endophytic microorganisms. The mangrove plants are known for their unique and diverse metabolites and because of their intimate association with mangrove plants, the mangrove derived endophytic microorganisms are explored for structurally unprecedented bioactive natural products. Mangrove endophytes represent a rich source of bioactive metabolites and are promising source of novel constituents. A systematic investigation of their metabolites may lead to the discovery of novel bioactive agents with useful medicinal and pharmaceutical applications. Therefore, in this review article an attempt has been made to summarize the different metabolites derived from the mangrove endophytes along with their potential pharmacological role for possible pharmaceutical exploitations.

Evaluation of In Vitro Antidiabetic and Antioxidant Activities andPreliminary Phytochemical Screening of Leaf Extracts of Avicenniaofficinalis

Avicennia officinalis is a medicinal mangrove plant and used in traditional folk medicine for treatment of various ailments. In the present study, the antidiabetic and antioxidant activities of petroleum ether and aqueous extracts of leaves of A. officinalis were evaluated. The antidiabetic activity was evaluated out by α-amylase and α-glucosidase inhibition study and antioxidant capacity by DPPH, superoxide and hydrogen peroxide scavenging activity of leaf extracts at various concentrations. The maximum antidiabetic activity was observed in 1.0 mg/ml of leaves extract of aqueous extracts. The maximum superoxide and hydrogen peroxide scavenging activity were exhibited by aqueous extracts with IC50 values of 0.27 and 0.17 mg/ml respectively and maximum DPPH scavenging activity was shown by petroleum ether extracts with IC50 value of 0.25 mg/ml. The qualitative and quantitative phytochemical analysis also showed presence of different phytochemicals including phenols, flavonoids and tannins which may be attributed to their antidiabetic and antioxidant activities. Thus, the present study gives a clear evidence that leaf extracts of A. officinalis possess both antidiabetic and antioxidant activities.

In Vitro Antidiabetic and Antioxidant Potentials of Leaf and Stem Bark Extracts of a Mangrove Plant, Xylocarpus granatum

ABSTRACT Ethanol, methanol and aqueous leaf and stem bark extracts of Xylocarpus granatum (Meliaceae), a mangrove plant, were evaluated for their antidiabetic and antioxidant potentials. While the ethanol bark extracts exhibited the highest α-glucosidase inhibitory activity, the ethanol leaf extracts showed highest glucose uptake by yeast cells. The methanol and aqueous extracts of bark and methanol extracts of leaf showed highest antioxidant activities with the IC50 values of 41.40, 91.82 and 106.98 μg mL−1 for DPPH, superoxide and H2O2 scavenging assays respectively. The ethanol bark extracts possess highest phenolic content with a value of 347.5 mg/g catechol equivalents.