Studies on the possible mechanisms of antidiabetic activity of extract of aerial parts of Phyllanthus niruri

Phytochemical Screening, In Silico Molecular Docking, ADME Properties, and In Vitro Antioxidant, Anticancer, and Antidiabetic Activity of Marine Halophyte Suaeda maritima (L.) Dumort

Medicinally valuable components derived from natural resources are highly desirable as prospective alternatives to synthetic drugs to treat fatal diseases, such as cancer and diabetes mellitus. Suaeda maritima (L.) Dumort (Amaranthaceae) (S. maritima) is a halophyte plant that can thrive in saline environments and possesses excellent medicinal properties. Hence, for the present investigation, S. maritima has been chosen, and its phytochemical constituents have been extracted utilizing various solvents, including hexane, acetone, and methanol, and identified by GC-MS, LC-MS, and HPLC analyses. The antioxidant activity of the compounds using DPPH, ABTS, and reducing power assays demonstrated that all three extracts of S. maritima possessed significant radical scavenging activity comparable to standard ascorbic acid with lower IC50 values (69.20-95.58 μg/mL). In addition, the evaluation of antidiabetic activity by α-amylase inhibition and α-glucosidase inhibition methods revealed that the acetone extract of S. maritima (SMAE) displayed equipotent activity of standard acarbose with an IC50 of 32.6 μg/mL. Advantageously, SMAE also exhibited better inhibition activity against the growth of lung cancer cells with an IC50 of 78.19. μg/mL and less toxicity on the noncancerous HUVEC cells with a high IC50 of 300 μg/mL. In addition, the cancer cell death mechanism via the apoptotic pathway induced by SMAE was confirmed by DAPI staining and ROS analysis. The analysis of ADME properties, including absorption, distribution, metabolism, and excretion, witnessed that the physicochemical and druglikeness factors were best catered by stigmasterol, γ-sitosterol, and vitamin E. Further, the key phytochemicals identified from SMAE were docked with CtBP1 and SOX2 bound to importin-α target proteins associated with carcinogenic pathways using Schrodinger software. The results showed that the phytochemicals, scilicet, stigmasterol, γ-sitosterol, octadecadienoic acid, and vitamin E, showed a good binding affinity with Glide scores in the range -2.845-4.018 kcal/mol. Overall, the findings support that the least investigated traditional edible medicinal mangrove-related S. maritima is high in pharmacologically active constituents and might be one of the finest sources of naturally derived molecules for drug development and delivery systems.

A randomized placebo-compared study on the efficacy of classical ayurvedic pharmaceutical form versus aqueous alcoholic extracts of Phyllanthus niruri Linn. Plus Sida cordifolia Linn. In patients of diabetic sensory polyneuropathy

Background

In routine, Ayurveda practitioners prefer classical pharmaceutical form of herbal medicines in compare to modern extracts.

Objective

To explore the difference of efficiency between whole drug powder of Phyllanthus niruri plus root decoction of Sida cordifolia and modern extracts of the same in compared to placebo in patients of diabetic poly-neuropathy.

Material and methods

A randomized, partly-double-blinded, placebo-controlled trial evaluated the efficacy of two different pharmaceutical forms of herbal medicines over placebo in 90 patients (30 in each group) of diabetic sensory polyneuropathy for first three weeks period. After three weeks, active herbal medication groups were continued with their assigned medicaments for next 5 weeks period and all placebo-patients were randomized again into 2 groups of active medication and treated for next 8 weeks. Patients were assessed with Neuropathy Total Symptom Score 6 and sensation thresholds.

Results

Significant effect of both form of herbal medicines over placebo was found in aching pain [F (2, 49) = 6.79, p = 0.002], allodynia [F (2, 59) = 6.74, p = 0.002], burning pain [F (2, 82) = 14.66, p < 0.0001], numbness [F (2, 77) = 16.37, p < 0.0001] and pricking pain [F (2, 50) = 14.23, p < 0.0001]. After the 8 weeks period, no significant difference was identified between the effect of both the herbal treatment on aching pain (U = 220, p = 0.03), allodynia (U = 421.5, p = 0.29), burning pain (U = 881.5, p = 0.846), numbness (U = 778, p = 0.92) and pricking pain (U = 260, p = 0.15).

Conclusion

Both herbal groups have significant effect to reduce NTSS-6 score in compare to placebo. No significant difference found between the effect of two different pharmaceutical forms of Phyllanthus niruri and S. cordifolia.

•Ayurvedist prefer more classical pharmaceutical form than modern extracts of herbs.

•In this RCT, after 3 weeks period, placebo patients randomized again in both active herbal groups.

•Multiple statistical tests applied for each outcome variable.

•Both herbal groups have significant effect to reduce the NTSS-6 score in compare to placebo.

•No significant difference found between the effect of classical pharmaceutical forms and modern extract form of herbs.

Antidiabetic Potential of Plants from the Caribbean Basin

Diabetes mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia, insulin insufficiency or insulin resistance, and many issues, including vascular complications, glycative stress and lipid metabolism dysregulation. Natural products from plants with antihyperglycemic, hypolipidemic, pancreatic protective, antioxidative, and insulin-like properties complement conventional treatments. Throughout this review, we summarize the current status of knowledge of plants from the Caribbean basin traditionally used to manage DM and treat its sequelae. Seven plants were chosen due to their use in Caribbean folk medicine. We summarize the antidiabetic properties of each species, exploring the pharmacological mechanisms related to their antidiabetic effect reported in vitro and in vivo. We propose the Caribbean flora as a source of innovative bioactive phytocompounds to treat and prevent DM and DM-associated complications.

Screening natural product extracts for potential enzyme inhibitors: protocols, and the standardisation of the usage of blanks in α-amylase, α-glucosidase and lipase assays

BACKGROUND

Enzyme assays have widespread applications in drug discovery from plants to natural products. The appropriate use of blanks in enzyme assays is important for assay baseline-correction, and the correction of false signals associated with background matrix interferences. However, the blank-correction procedures reported in published literature are highly inconsistent. We investigated the influence of using different types of blanks on the final calculated activity/inhibition results for three enzymes of significance in diabetes and obesity; α-glucosidase, α-amylase, and lipase. This is the first study to examine how different blank-correcting methods affect enzyme assay results. Although assays targeting the above enzymes are common in the literature, there is a scarcity of detailed published protocols. Therefore, we have provided comprehensive, step-by-step protocols for α-glucosidase-, α-amylase- and lipase-inhibition assays that can be performed in 96-well format in a simple, fast, and resource-efficient manner with clear instructions for blank-correction and calculation of results.

RESULTS

In the three assays analysed here, using only a buffer blank underestimated the enzyme inhibitory potential of the test sample. In the absorbance-based α-glucosidase assay, enzyme inhibition was underestimated when a sample blank was omitted for the coloured plant extracts. Similarly, in the fluorescence-based α-amylase and lipase assays, enzyme inhibition was underestimated when a substrate blank was omitted. For all three assays, method six [Raw Data - (Substrate + Sample Blank)] enabled the correction of interferences due to the buffer, sample, and substrate without double-blanking, and eliminated the need to add substrate to each sample blank.

CONCLUSION

The choice of blanks and blank-correction methods contribute to the variability of assay results and the likelihood of underestimating the enzyme inhibitory potential of a test sample. This highlights the importance of standardising the use of blanks and the reporting of blank-correction procedures in published studies in order to ensure the accuracy and reproducibility of results, and avoid overlooked opportunities in drug discovery research due to inadvertent underestimation of enzyme inhibitory potential of test samples resulting from unsuitable blank-correction. Based on our assessments, we recommend method six [RD - (Su + SaB)] as a suitable method for blank-correction of raw data in enzyme assays.

Maternal-fetal repercussions of Phyllanthus niruri L. treatment during rat pregnancy

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus niruri is a well-known plant for its therapeutic purposes to treat various diseases, being widely used by the population, mainly by women. However, there is no scientific confirmation of the effects of use during pregnancy.

AIM OF THE STUDY

Evaluating the effect of Phyllanthus niruri aqueous extract on the maternal toxicity, reproductive outcomes and fetal anomaly incidence in rats.

MATERIALS AND METHODS

Pregnant rats were distributed into four experimental groups: Control = treated with water (vehicle); Treated 150 = treated with P. niruri at dose 150 mg/kg and; Treated 300 = treated with P. niruri at dose 300 mg/kg; and Treated 600 = treated with P. niruri at dose 600 mg/kg. The rats were treated by intragastric route (gavage) with P. niruri or vehicle (water) from gestational day 0 to 21. At day 21 of pregnancy, maternal reproductive outcomes, biochemical profile and maternal renal tissue were evaluated. The fetuses and placentas were collected and analyzed.

RESULTS

Treatment with P. niruri did not alter the reproductive performance outcomes of rats. However, treated 600 group presented with changes in maternal kidney weight and morphology. The plant did not present teratogenic effect, but caused fetal macrosomia and increased ossification sites.

CONCLUSION

Treatment with aqueous extract of P. niruri administered during gestation did not cause reproductive toxicity, but led to changes in maternal kidneys and in offspring weight, showing that the leaf extract of this plant can produce detrimental effects during pregnancy.

Anabasis aretioides Coss. & Moq. phenolic compounds exhibit in vitro hypoglycemic, antioxidant and antipathogenic properties

Background Based on our previous ethnobotanical survey, the non-investigated Saharan plant Anabasis aretioides Coss. & Moq., growing in the region of Errachidia, was selected for pharmacological investigation. In Moroccan traditional medicine, A. aretioides is being used for diabetes treatment. Thus, the current work aims at evaluating the antidiabetic, antioxidant, and antibacterial activities of the plant in relation to the digestive tract. Methods The different parts of the plant (aerial parts, roots, seeds) were extracted with methanol (MeOH) and screened in enzymatic assays for their inhibitory potential against α-amylase and α-glucosidase, as well as antioxidant and antibacterial activities. Furthermore, the phenolic compounds were analyzed using HPLC-DAD-QTOF-MS. Results The MeOH extracts of A. aretioides aerial parts, roots, and seeds, respectively, inhibited α-amylase (IC50 of 3148.07 μg/mL, 2440.20 μg/mL, 3395.71 μg/mL) and α-glucosidase (IC50 of 2940.59 μg/mL, 3521.81 μg/mL, 3393.83 μg/mL). Moreover, compared to aerial parts and seeds, the plant roots exhibited higher antioxidant capacity and a potent reducing power. In resazurin microplate assay, the plant parts displayed a minimal inhibitory concentration (MIC) ranging from 7.81 mg/mL to 31.25 mg/mL. Chemical analysis revealed 25 phenolic compounds, with chlorogenic acid as the main phenolic compound in the aerial parts, hesperidin in roots, and quercitrin in seeds. Conclusion Anabasis aretioides cited for treatment of diabetes shows promising antioxidant and antibacterial properties, as well as an ability to inhibit digestive enzyme, including α-amylase and α-glucosidase. Thus, our results explain in part the traditional use of this Saharan medicine and open doors for further in vivo mechanistic and functional studies.

Investigation of antidiabetic potential of Phyllanthus niruri L. using assays for α-glucosidase, muscle glucose transport, liver glucose production, and adipogenesis

Phyllanthus niruri is used in herbal medicine for treatment of diabetes. The objective of this study was to investigate the antidiabetic potential of P. niruri, using assays for α-glucosidase, muscle glucose transport, liver glucose production and adipogenesis. α-Glucosidase inhibitory activity was performed on aqueous and ethanolic extract of aerial parts of P. niruri. The aqueous and ethanolic extract of P. niruri showed α-glucosidase inhibitory activity with IC₅₀ values of 3.7 ± 1.1 and 6.3 ± 4.8 μg/mL, respectively. HR-bioassay/HPLC-HRMS and NMR analysis was used for identification of compounds. Corilagin (1) and repandusinic acid A (2) were identified as α-glucosidase inhibitors in the water extract of P. niruri with IC₅₀ values of 0.9 ± 0.1 and 1.9 ± 0.02 μM, respectively. In in vitro cell-based bioassays, cells were treated for 18 h with maximal non-toxic concentrations of the ethanolic extract of P. niruri, which were determined by the lactate dehydrogenase cytotoxicity assay. The ethanolic extract of P. niruri was not able to reduce glucose-6-phosphatase activity. However, the extract increased deoxyglucose uptake in C2C12 muscle cells and enhanced adipogenesis in 3T3-L1 fat cells which has been reported for the first time. The present study demonstrated that P. niruri may thus have potential application for treatment and/or management of type 2 diabetes.

Interactions between antidiabetic drugs and herbs: an overview of mechanisms of action and clinical implications

Diabetes is a complex condition with a variety of causes and pathophysiologies. The current single target approach has not provided ideal clinical outcomes for the treatment of the disease and its complications. Herbal medicine has been used for the management of various diseases such as diabetes over centuries. Many diabetic patients are known to use herbal medicines with antidiabetic properties in addition to their mainstream treatments, which may present both a benefit as well as potential risk to effective management of their disease. In this review we evaluate the clinical and experimental literature on herb-drug interactions in the treatment of diabetes. Pharmacokinetic and pharmacodynamic interactions between drugs and herbs are discussed, and some commonly used herbs which can interact with antidiabetic drugs summarised. Herb-drug interactions can be a double-edged sword presenting both risks (adverse drug events) and benefits (through enhancement). There is a general lack of data on herb-drug interactions. As such, more rigorous scientific research is urgently needed to guide clinical practice as well as to safeguard the wellbeing of diabetes patients.

Phyllanthus niruri leaves aqueous extract improves kidney functions, ameliorates kidney oxidative stress, inflammation, fibrosis and apoptosis and enhances kidney cell proliferation in adult male rats with diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Phylanthus niruri has been used to treat ailments related to the urogenital organs. In this study, this herb was hypothesized to help to ameliorate kidney disease in diabetes mellitus (DM).

AIMS

To investigate P. niruri leaves aqueous extract (PN) effects on kidney functions, histopathological changes and levels of oxidative stress, inflammation, fibrosis, apoptosis and proliferation in DM.

METHODS

PN was orally administered to streptozotocin-nicotinamide-induced male diabetic rats for 28 days. At the end of the treatment, fasting blood glucose (FBG) and kidney functions were measured. Kidney somatic index, histopathological changes and levels of RAGE, Nrf2, oxidative stress markers (TBARS, SOD, CAT and GPx), inflammatory markers (NFkβ-p65, Ikk-β, TNF-α, IL-1β and IL-6), apoptosis markers (caspase-3, caspase-9 and Bax), fibrosis markers (TGF-β1, VEGF and FGF-1) and proliferative markers (PCNA and Ki-67) were determined by biochemical assays, qPCR, Western blotting, immunohistochemistry or immunofluorescence.

RESULTS

Administration of PN helps to maintain near normal FBG, creatinine clearance (CCr), blood urea nitrogen (BUN), BUN/Cr ratio, serum electrolytes, uric acid and urine protein levels in DM. Decreased RAGE, TBARS and increased Nrf2, SOD-1, CAT and GPx-1 were observed in PN-treated diabetic rat kidneys. Expression of inflammatory, fibrosis and apoptosis markers in the kidney reduced but expression of proliferative markers increased following PN treatment. Lesser histopathological changes were observed in the kidney of PN-treated diabetic rats.

CONCLUSION

PN helps to preserve near normal kidney function and prevents histopathological changes via ameliorating oxidative stress, inflammation, fibrosis and apoptosis while enhancing proliferation of the kidney in DM.

Plants used to treat diabetes in Sri Lankan Siddha Medicine - An ethnopharmacological review of historical and modern sources

INTRODUCTION AND BACKGROUND

In recent decades diabetes mellitus has become a considerable health problem in countries like Sri Lanka and results in an increasing economic burden hampering the social and economic development of these countries. About 60% to 70% of the rural population in Sri Lanka rely on indigenous medicinal systems as their main source for primary health care. Siddha (Tamil) Medicine is one of the four Sri Lankan traditional medicinal systems and it is practised mostly in the eastern and northern provinces of Sri Lanka where the majority of Tamils reside.

AIM

The foundation of this study is a documentation of plant species recorded in historical and modern Sri Lankan Siddha Medical documents used to treat diabetes. Based on the systematic documentation and analysis of Siddha concepts about diabetes and its signs and preparations used to treat diabetes in Sri Lankan Siddha Medicine, the plant species included in these preparations (excluding globally or very widely used, very well studied species) were evaluated in terms of the current state-of-the-art about these species' pharmacology and effectiveness in order to lay a foundation for their further development.

METHOD

Historic and modern Sri Lankan university texts books in Tamil were used as sources for information on diabetes Siddha concepts and antidiabetic Sri Lankan Siddha Medicine preparations. Information on the known antidiabetic effects of extracts and compounds obtained from these species were used in order to assess the current state of the art of these species.

RESULTS AND DISCUSSION

Information of ingredients, preparation methods, amount of ingredients used, and dosages of 60 antidiabetic Sri Lankan Siddha Medicine preparations were obtained. Animal parts including marine organisms, inorganic substances, and plants are the three types of ingredients used. Overall 171 plant species in 73 families were documented. Senna auriculata (L.) Roxb. (Fabaceae) was identified as the most frequently cited species. Globally distributed and very well studied plants were excluded in the pharmacological and clinical literature review which includes 123 plant species. The majority (48%) of the plant species reviewed were studied up to in vivo level as the current maximum level of scientific evidence available. Followed by 41% of species have not been studied for antidiabetic activities or did not show antidiabetic activity. Moreover, 6% and 5% were studied up to in vitro and in clinical levels, respectively. The majority of the species were studied only in the models that represent type 1 diabetes.

CONCLUSION

This is the first study systematically assessing the importance of preparations and plants used in antidiabetic Sri Lankan Siddha Medicine preparations. Antidiabetic plants are a crucial health care resource in Sri Lankan Siddha Medicine. This study also identified a wide range of methodological problems in the studies conducted so far. More and better type 2 diabetes models should be employed in future studies. This comprehensive review creates the basis for a more systematic study of these local resources.

Ocimum basilicum extract exhibits antidiabetic effects via inhibition of hepatic glucose mobilization and carbohydrate metabolizing enzymes

Aim:

Ocimum basilicum L (Lamiaceae) is used as a traditional remedy for different ailments, including diabetes mellitus. This study investigated the antidiabetic effects of an extract of aerial parts of O. basilicum.

Methods:

Antihyperglycemic effect of the extract was determined by its effects on α-amylase and α-glucosidase in vitro, while antidiabetic properties were studied in alloxan induced diabetic rats treated for 28 days with extract and compared to those treated with oral metformin (150 mg/kg). The study and analysis was conducted between 2014 and 2015.

Results:

The treatment with 100 and 200 mg/kg extract significantly (P < 0.05) reduced fasting blood glucose concentration and slightly increased mean body weight in treated groups. Oral glucose tolerance was also significantly (P < 0.05, 0.001) improved in 100 and 400 mg/kg extract-treated groups. The extract caused a dose-dependent increase in liver glycogen content, while it decreased alanine transferase (18.9-30.56%) and aspartate transferase (6.48-34.3%) levels in a non-dose-dependent manner. A dose of 100 mg/kg also reduced serum cholesterol and triglycerides by 19.3 and 39.54%, compared to a 2.6% reduction of cholesterol seen in the metformin-treated group. The extract was observed to produce significant (P < 0.001) concentration-dependent inhibition of α-glucosidase (35.71-100%) and also α-amylase (23.55-81.52%), with estimated inhibitory concentration values of 1.62 and 3.86 mg/mL, respectively.

Conclusions:

The antidiabetic properties of the extract may be due to its ability to suppress endogenous glucose release, inhibit glycogenolysis and/or stimulate glycogenesis.

Bioguided Fraction and Isolation of the Antitumor Components from Phyllanthus niruri L

Phyllanthus niruri L., a well-known medicinal plant, has been used as a folk antitumor remedy in the worldwide scale. However, the antitumor components in P. niruri have not been reported. In order to verify the antitumor components of P. niruri and the plants which have the high content of these components, we isolated the antitumor components with bioguided fraction and isolation, by different chromatographic methods from the ethyl acetate fraction of P. niruri., and identified them as ethyl brevifolincarboxylate and corilagin by ¹H-NMR, ¹³C-NMR, 2D-NMR, and mass spectrometric analyses. Cell cytotoxicity assays showed that corilagin has broad-spectrum antitumor activity, a better antitumor potential, and lower toxicity in normal cells. Besides, the coefficient of drug interaction (CDI) of 10 μM corilagin and 20 μM cDDP reached up to 0.77, which means corilagin can promote the antitumor activity of cDDP. Furthermore, by the extensive screening among 10 species of plants reported to contain corilagin, we found that Dimocarpus longan Lour. has the maximum content of corilagin. In conclusion, corilagin is the major active antitumor composition in P. niruri. L. on HCC cells and has high content in D. longan.

The pharmacological potential of Phyllanthus niruri

INTRODUCTION

Phyllanthus niruri is a traditional shrub of the genus Phyllanthaceae with long-standing Ayurvedic, Chinese and Malay ethnomedical records. Preliminary studies from cell and animal model have provided valuable scientific evidence for its use.

AIM

This review aims to summarize selected scientific evidence on the pharmacological properties of P. niruri over the past 35 years while identifying potential areas of further development of this herb as an economical adjunct.

METHODS

The review covers literature pertaining to the evidence base therapeutic potential of P. niruri spanning from 1980 to 2015 available on PubMed.

RESULTS

Evidence suggests that the extracts of P. niruri possess hepatoprotective, antiviral, antibacterial, hypolipidaemic, hypoglycaemic, analgesic, anti-inflammatory, cardioprotective, anti-urolithiatic and antihyperuricaemic properties due its novel bioactive compounds.

CONCLUSION

Scientific evidence suggests that there is strong pharmacological potential in developing P. niruri as a drug to be used in liver disorders and in antiviral therapy. Despites this, large-scale heterogeneity in study protocol and unstandardized reporting standards limit the ability for valuable comparison and may mask the ability to replicate these studies. Thus interpretation of findings should be performed with caution and further studies should be performed in line with best practices. More cheminformatics, toxicological and mechanistic studies would aid the progress to clinical trial studies.

Relationship Between Metabolites Composition and Biological Activities of Phyllanthus niruri Extracts Prepared by Different Drying Methods and Solvents Extraction

The study investigated the changes in the metabolite, antioxidant and α-glucosidase inhibitory activities of Phyllanthus niruri after three drying treatments: air, freeze and oven dryings. Water extracts and extracts obtained using different solvent ratios of ethanol and methanol (50, 70, 80 and 100%) were compared. The relationships among the antioxidant, α-glucosidase inhibitory activity and metabolite levels of the extracts were evaluated using partial least-square analysis (PLS). The solvent selectivity was assessed based on the phytochemical constituents present in the extract and their concentrations quantitatively analyzed using high performance liquid chromatography. The freeze-dried P. niruri samples that were extracted with the mixture of ethanol or methanol with low ratio of water showed higher biological activity values compared with the other extracts. The PLS results for the ethanolic with different ratio and water extracts demonstrated that phenolic acids (chlorogenic acid and ellagic acid) and flavonoids were highly linked to strong α-glucosidase inhibitory and antioxidant activities.

Aqueous Extract of Phyllanthus niruri Leaves Displays In Vitro Antioxidant Activity and Prevents the Elevation of Oxidative Stress in the Kidney of Streptozotocin-Induced Diabetic Male Rats

P. niruri has been reported to possess antidiabetic and kidney protective effects. In the present study, the phytochemical constituents and in vitro antioxidant activity of P. niruri leaf aqueous extract were investigated together with its effect on oxidative stress and antioxidant enzymes levels in diabetic rat kidney. Results. Treatment of diabetic male rats with P. niruri leaf aqueous extract (200 and 400 mg/kg) for 28 consecutive days prevents the increase in the amount of lipid peroxidation (LPO) product, malondialdehyde (MDA), and the diminution of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity levels in the kidney of diabetic rats. The amount of LPO showed strong negative correlation with SOD, CAT, and GPx activity levels. P. niruri leaf aqueous extract exhibits in vitro antioxidant activity with IC₅₀ slightly lower than ascorbic acid. Phytochemical screening of plant extract indicates the presence of polyphenols. Conclusion. P. niruri leaf extract protects the kidney from oxidative stress induced by diabetes.

Ethnomedicinal application of native remedies used against diabetes and related complications in Mauritius

ETHNOPHARMACOLOGICAL RELEVANCE

Notoriously, the tropical island of Mauritius has one of the highest prevalence of diabetes worldwide and the economic burden associated with it is alarming. The use of native remedies (NRs) is well anchored in the local culture and it continues to be the cornerstone of therapy for diabetic patients. However, there is currently a dearth of updated primary data on NRs used by Mauritians against diabetes and diabetes related complications (DRCs). This study was therefore designed to record, analyze and document orally transmitted ethnopharmacological knowledge from diabetic patients and traditional medicine practitioners (TMPs) in Mauritius concerning NRs commonly used against diabetes and DRCs which might open new avenues to initiate novel antidiabetic drugs discovery.

MATERIALS AND METHODS

Data was collected following interviews from diabetic patients (n=328) and TMPs (n=20). Eleven quantitative indexes, namely informant consensus factor (FIC), fidelity level (FL), use value (UV), relative frequency of citation (RFC), relative importance (RI), cultural importance index (CII), index of agreement on remedies (IAR), cultural agreement index (CAI), quality use value (QUV), quality use agreement value (QUAV) and ethnobotanicity index (EI) were calculated. Statistical analysis such as Pearson correlation and Chi-squared test were performed to determine any association.

RESULTS

A total of 111 plant species distributed over 56 families, 30 polyherbal formulations and 16 animal species were documented to be traditionally used against diabetes and DRCs. For the first time 8 endemic plants have been recorded to be used against diabetes and DRCs from Mauritius. The most encountered medicinal plant family was Asteraceae. According to the EI, 16.2% of the native plants in Mauritius were used against diabetes and DRCs. As far as we know, Vangueria madagascariensis, Apium graveolens, Petroselinum crispum and Rubus alceifolius with high RFC values are recorded against diabetes and DRCs for the first time. Sociodemographic characteristics (age, gender, income, religious belief, education and residence) were found to significantly (p<0.05) influence the use of NRs. The average FIC for all ailments for plant and animal products were 0.94 and 0.87 respectively. Bryophyllum pinnatum, a native plant to Mauritius scored a high FL value (100%) used against diabetic neuropathy, Allium sativum had the highest RI value (2.00) due to its versatility, Aloe vera had the highest RFC (0.61), the CII (0.640) and the highest CAI value (0.635), Psidium guajava had the highest QUAV (0.961) which indicates its high bioactivity and Allium cepa was reported as the most effective plant species (QUV=0.965). According to UV, the most important species was Morinda citrifolia (1.21). Panoply of animal products were reported whereby fish (39.7%) was recorded as the most utilised zootherapy and Salmo salar scored the highest FL (100%) for diabetes. Some animal species (n=14) not previously documented against diabetes and DRCs are reported in the present study.

CONCLUSION

Our present investigation revealed that the use of NRs constitutes the common legacy of Mauritians and despite the penetration of allopathic medicine; NRs continue to play a crucial role in the primary health care system of Mauritius. To this effect, it is of uttermost importance to record this knowledge before it disappears. In addition, further experimental investigations are required to elucidate the pharmacological properties of the reported medicinal flora and fauna of Mauritius.

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.

Antidiabetic effects of rice hull smoke extract in alloxan-induced diabetic mice

This study investigated the protective effect of a liquid rice hull smoke extract (RHSE) against diabetes in alloxan-induced diabetic mice. Antidiabetic effects of RHSE were evaluated in both the rat insulinoma-1 cell line (INS-1) and diabetic ICR mice induced by intraperitoneal (ip) injection of alloxan. Alloxan treatment (10 mM) increased cellular reactive oxygen species (ROS) levels in the INS-1 cells, which were inversely related to cell viabilities. RHSE inhibited alloxan-induced nitric oxide (NO) generation through inhibition of inducible nitric oxide synthase (iNOS) gene expression and suppressed the inflammatory reaction in INS-1 cells through inhibition of expression of pro-inflammatory genes, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Dietary administration of 0.5 or 1% RHSE to alloxan-induced diabetic mice caused a decrease in blood glucose and increases in both serum insulin and hepatic glycogen levels. RHSE induced decreases in glucose-6-phosphatase (G6 Pase) and phosphoenolpyruvate carboxykinase (PEPCK) levels and an increase in the glucokinase (GCK) level. These changes resulted in restoring glucose-regulating enzyme levels to control values. Histopathology showed that alloxan also induced damage of Langerhans islet cells of the pancreas and liver necrosis associated with diabetes. Oral administration of RHSE restored the islet and liver cells to normal levels. RHSE-supplemented functional food could protect insulin-producing islet cells against damage triggered by oxidative stress and local inflammation associated with diabetes.