COX-2 and sPLA2 inhibitory activity of aqueous extract and polyphenols of Rhizophora mangle (red mangrove)

Evidence for the efficacy of anti-inflammatory plants used in Brazilian traditional medicine with ethnopharmacological relevance

ETHNOPHARMACOLOGICAL RELEVANCE

When exacerbated, inflammatory processes can culminate in physical and emotional disorders and, if not stopped, can be lethal. The high prevalence of inflammation has become a public health problem, and the need for new drugs to treat this pathology is imminent. The use of medicinal plants has emerged as an alternative, and a survey of data that corroborates its application in inflammatory diseases is the starting point. Furthermore, Brazil harbors a megadiversity, and the traditional use of plants is relevant and needs to be preserved and carefully explored for the discovery of new medicines.

AIM OF THE STUDY

This review sought to survey the medicinal plants traditionally used in Brazil for the treatment of inflammatory processes and to perform, in an integrative way, a data survey of these species and analysis of their phytochemical, pharmacological, and molecular approaches.

MATERIALS AND METHODS

Brazilian plants that are traditionally used for inflammation (ophthalmia, throat inflammation, orchitis, urinary tract inflammation, ear inflammation, and inflammation in general) are listed in the DATAPLAMT database. This database contains information on approximately 3400 native plants used by Brazilians, which were registered in specific documents produced until 1950. These inflammatory disorders were searched in scientific databases (PubMed/Medline, Scopus, Web of Science, Lilacs, Scielo, Virtual Health Library), with standardization of DECS/MESH descriptors for inflammation in English, Spanish, French, and Portuguese, without chronological limitations. For the inclusion criteria, all articles had to be of the evaluated plant species, without association of synthesized substances, and full articles free available in any of the four languages searched. Duplicated articles and those that were not freely available were excluded.

RESULTS

A total of 126 species were identified, culminating in 6181 articles in the search. After evaluation of the inclusion criteria, 172 articles representing 40 different species and 38 families were included in the study. Comparison of reproducibility in intra-species results became difficult because of the large number of extraction solvents tested and the wide diversity of evaluation models used. Although the number of in vitro and in vivo evaluations was high, only one clinical study was found (Abrus precatorius). In the phytochemical analyses, more than 225 compounds, mostly phenolic compounds, were identified.

CONCLUSION

This review allowed the grouping of preclinical and clinical studies of several Brazilian species traditionally used for the treatment of many types of inflammation, corroborating new searches for their pharmacological properties as a way to aid public health. Furthermore, the large number of plants that have not yet been studied has encouraged new research to revive traditional knowledge.

HPLC characterization, acute and sub-acute toxicity evaluation of bark extract of Rhizophora mucronata in Swiss Albino mice

Aim

Rhizophora mucronata, commonly called as 'red mangrove' grows in the tropical and sub-tropical regions and on the sheltered shores. The bioactive compounds from the plant have been used in the treatment of wide range of diseases. Though the beneficial effects have been reported, the safety and toxicological studies are not carried out. Hence, major bioactives have been identified by HPLC and then acute and sub-acute toxicity studies of (BERM) in Swiss Albino mice have been carried out.

Main methods

HPLC fingerprinting was carried out of BERM for the characterization of bioactives. BERM as a single dose was given orally at 800, 1600 mg/kg and 3200 mg/kg by a stainless steel cannula to the mice. Then the mice were observed for 14 days for mortality and behavioural changes. Food, water intake and body weight changes were also observed throughout the study period. On the fifteenth day, the mice were anesthetized with isofluorane and blood was withdrawn for haematological and biochemical analysis. The animals were sacrificed by overdose of isofluorane and organs such as liver, kidney, lungs and spleen were dissected out for histopathological analysis. There was no mortality of the mice even in 3200 mg/kg dose, stating that the oral LD50 of BERM is more than 5000 mg/kg. In terms of Sub-acute toxicity, for a period of 28 days repeated dose of 400 mg/kg and 800 mg/kg as an optimum dose and a control group was kept with only distilled water at 5 ml/kg against the treated groups. On 29^th day, the mice from all groups were sacrificed and blood was withdrawn and organs such as liver, kidney, lungs and spleen were dissected out for the assessment of internal tissues, wherein no abnormalities were observed in the treatment groups as compared to the control. The blood parameters, biochemical analysis of the treated groups were well within the range, histopathological confirmed the findings wherein the organs viz, liver, kidneys, lungs and spleen possessed normal architecture.

Key findings

Based on HPLC results, prominent 5 major compounds viz: Diadzein, Epicatechin, Hesperidin, Diosmin and Quercitrin respectively were identified. Isolated changes observed in the haematological, biochemical and histopathological studies were not dose related and showed the safety of the bark extract. Similarly, the sub-acute toxicity of BERM has been conducted for 28 days, wherein repeated dose of 400 mg/kg and 800 mg/kg and control group was given orally. There were no abnormalities found both in external and internal parameters.

Significance

Based on the study it is concluded that the bark extract of Rhizophora mucronata (BERM) is safe at 1000 mg/kg or less on repeated dosage can be considered as a safe dose for pharmacological efficacy studies.

Evaluation of embryotoxic and embryostatic effects of the aqueous extract of Rhizophora mangle and tannic acid on eggs and larvae of Aedes aegypti

Rhizophora mangle is an abundant plant in mangroves and tannic acid is a polyphenol produced by the secondary metabolism of plants. The aim of the study was to evaluate the embryotoxic and embriostatic effects of the aqueous extract of R. mangle and synthetic tannic acid on eggs and larvae of Aedes aegypti. A. aegypti eggs were exposed in duplicate at concentrations of 250, 500, 750 and 1000 µg/mL of extract and tannic acid for a period of 14 days. Mineral water was used as a negative control. The eggs were observed and counted in a stereomicroscope (1.2x). In all extract concentrations there was stimulation in hatching in relation to the control, but only in concentration of 750 mg/mL it was statistically significant. In tannic acid (250µg/ml) there was significant stimulus in hatching, but in 500, 750 and 1000 µg/mL there was significant inhibition. All concentrations of aqueous extract and tannic acid on larvae showed embryotoxic and embryostatic effects when compared to the control. The aqueous extract of R. mangle showed effect on hatching of A. aegypti eggs and synthetic tannic acid showed embryotoxic and embryostatic effects. On larvae, both the aqueous extract as tannic acid showed embryotoxic and embryostatic effects.

Pharmacological and Ethnomedicinal Overview of Heritiera fomes: Future Prospects

Mangrove plants are specialized woody plants growing in the swamps of tidal-coastal areas and river deltas of tropical and subtropical parts of the world. They have been utilized for medicinal and other purposes by the coastal people over the years. Heritiera fomes Buch. Ham. (family: Sterculiaceae) commonly known as Sundari (Bengali) is a preeminent mangrove plant occurring in the Sundarbans forest located in the southern part of Bangladesh and adjoining West Bengal province of India. The plant has applications in traditional folk medicine as evidenced by its extensive use for treating diabetes, hepatic disorders, gastrointestinal disorders, goiter, and skin diseases by the local people and traditional health practitioners. A number of investigations indicated that the plant possesses significant antioxidant, antinociceptive, antihyperglycemic, antimicrobial, and anticancer activities. Phytochemical analyses have revealed the presence of important chemical constituents like saponins, alkaloids, glycosides, tannins, steroids, flavonoids, gums, phytosterols, and reducing sugars. The present study is aimed at compiling information on phytochemical, biological, pharmacological, and ethnobotanical properties of this important medicinal plant, with a view to critically assess the legitimacy of the use of this plant in the aforementioned disorders as well as providing directions for further research.

Hypoglycemic effect of Rhizophora mucronata in streptozotocin induced diabetic rats

Rhizophora mucronata, plant of Mangroove family, found on the coastal region of India and used in treatment of various diseases. Different parts of plants are used in treatment of diabetes as folkloric medicine. The present study was designed to evaluate the hypoglycemic effect of hydro-alcoholic extract of R. mucronata. Streptozotocin (STZ)-induced diabetic rats were treated with RME (100 mg/kg and 200 mg/kg) and glibenclamide (0.5 mg/kg). Blood glucose levels were evaluated for the acute and sub-acute studies and body weight of rats were also monitored. All the treatments showed the highly significant (p<0.01) hypoglycemic effect in both the acute and the sub-acute studies. RME and glibenclamide treated rats were maintained the body weight during the study period while as the body weight of diabetic rats had gone down. The result of this study scientifically proved the hypoglycemic folkloric use of leaves of R. mucronata in treatment of diabetes.

Amazonian Brazilian medicinal plants described by C.F.P. von Martius in the 19th century

ETHNOPHARMACOLOGICAL RELEVANCE

Information regarding the use of beneficial, native Brazilian plants was compiled by European naturalists during the 19th century. The German botanist C.F.P. von Martius was one of the most prominent naturalists and described the use of several Brazilian plants.

AIM OF THE STUDY

To present data on Amazonian medicinal plants documented by von Martius in his books.

MATERIALS AND METHODS

Data on Amazonian medicinal plants were obtained from three books published by von Martius. Traditional information about these plants was translated from Latin and the cited plant species reorganised according to current taxonomic criteria. Correlated pharmacological studies were obtained from different scientific databases.

RESULTS

A total of 92 native medicinal species from the Amazon were recorded in von Martius' books. These accounts described 117 different medical uses for these plants. Several parts of the plants were used, including many exudates. The principal use of the species recorded was the treatment of dermatological problems, followed by gastro-intestinal, urinary and respiratory disorders. Few species were recorded as purgatives and febrifuges, a result that differs from the observations of other naturalists. The efficacy of the recorded traditional uses has been confirmed for the few species that have been subjected to laboratory studies.

CONCLUSION

The data recorded by the German naturalist von Martius represent a rich, unexplored source of information about the traditional uses of Brazilian plants.

Antioxidant action of mangrove polyphenols against gastric damage induced by absolute ethanol and ischemia-reperfusion in the rat

Rhizophora mangle, the red mangrove, has long been known as a traditional medicine. Its bark has been used as astringent, antiseptic, hemostatic, with antifungic and antiulcerogenic properties. In this paper, we aimed to evaluate the antioxidant properties of a buthanolic fraction of the R. mangle bark extract (RM) against experimental gastric ulcer in rats. Unib-Wh rats received pretreatment of R. mangle after the induction of gastric injury with absolute ethanol and ischemia-reperfusion. Gastric tissues from both methods were prepared to the enzymatic assays, the levels of sulfhydril compounds (GSH), lipid peroxides (LPO), and the activities of glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD) and myeloperoxidase (MPO) were measured. The RM protected the gastric mucosa in both methods used, ethanol-induced gastric ulcer and ischemia-reperfusion, probably, by modulating the activities of the enzymes SOD, GPx, and GR and increasing or maintaining the levels of GSH; in adittion, LPO levels were reduced. The results suggest that the RM antioxidant activity leads to tissue protection; thus one of the antiulcer mechanisms present on the pharmacological effects of R. mangle is the antioxidant property.

Antimicrobial activity of mangrove plant (Lumnitzera littorea)

OBJECTIVE

To investigate the antimicrobial activities of n-hexane, ethyl acetate and methanol extracts of the leaves of Lumnitzera littorea (L. littorea) against six human pathogenic microbes.

METHODS

The antimicrobial activity was evaluated using disc diffusion and microdilution methods.

RESULTS

The antimicrobial activities of the crude extracts were increased with increasing the concentration. It is clear that n-hexane extract was the most effective extract. Additionally, Gram positive Bacillus cereus (B. cereus) appear to be the most sensitive strain while Pseudomonas aeruginosa (P. aeruginosa) and the yeast strains (Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans)) appear to be resistance to the tested concentrations since no inhibition zone was observed. The inhibition of microbial growth at concentration as low as 0.04 mg/mL indicated the potent antimicrobial activity of L. littorea extracts.

CONCLUSIONS

The obtained results are considered sufficient for further study to isolate the compounds responsible for the activity and suggesting the possibility of finding potent antibacterial agents from L. littorea extracts.

1,1-Diphenyl-2-picrylhydrazyl radical and superoxide anion scavenging activity of Rhizophora mangle (L.) bark

Background:

Rhizophora mangle (L.) produce a variety of substances that possesses pharmacological actions. Although it shown antioxidant properties in some assays, there is no available information about its effect on some free radical species. So the objective of the present research is to evaluate the DPPH radical and superoxide anion scavenging properties of R. mangle extract and its polyphenol fraction.

Methods:

Rhizophora mangle (L.) bark aqueous extract and its major constituent, polyphenols fraction, were investigated for their antioxidant activities employing 2 in vitro assay systems: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals scavenging.

Results:

IC₅₀ for DPPH radical-scavenging activity was 6.7 µg tannins/mL for extract and 7.6 µg tannins/mL for polyphenolic fraction. The extract showed better activity than its fraction (P < 0.05) in the DPPH radicals reducing power. Polyphenolic fraction exhibited better superoxide anion scavenging ability (IC₅₀ = 21.6 µg tannins/mL) than the extract (IC₅₀ = 31.9 µg tannins/mL). Antioxidant activities of both samples increased with the rise of tannins concentration. The comparison of regression lines showed significant differences (P < 0.05) between extract and its polyphenolic fraction in both assays, indicating that extract was more effective in DPPH radical scavenging than its fraction at tannin concentrations below the crossing point of both lines, while that fraction was more effective than extract inhibiting the superoxide anions generation.

Conclusions:

R. mangle aqueous extract showed a potent antioxidant activity, achieved by the scavenging ability observed against DPPH radicals and superoxide anions. Regarding its polyphenolic composition, the antioxidant effects observed in this study are due, most probably, to the presence of polyphenolic compounds.

Flavanol derivatives from Rhizophora stylosa and their DPPH radical scavenging activity

A new acetylated flavanol, 3,7-O-diacetyl (-)-epicatechin (3), and seven known flavanol derivatives, (-)-epicatechin (1), 3-O-acetyl (-)-epicatechin (2), 3,3',4',5,7-O-pentaacetyl (-)-epicatechin (4), (+)-afzelechin (5), (+)-catechin (6), cinchonain Ib (7), and proanthocyanidin B2 (8), were isolated from the stems and twigs of the mangrove plant Rhizophora stylosa and identified. The crude extract, the different fractions and all of the purified compounds were evaluated for DPPH radical scavenging activity.