Elucidation of Mechanism of Action of Cassia auriculata Leaf Extract for Its Antidiabetic Activity in Streptozotocin-Induced Diabetic Rats

Ethnopharmacological, Phytochemical, Pharmacological, and Toxicological Review on Senna auriculata (L.) Roxb.: A Special Insight to Antidiabetic Property

Avartaki (Senna auriculata (L.) Roxb. syn. Cassia auriculata L.; Family- Fabaceae ) is a traditional medicinal plant, widely used for the treatment of various ailments in Ayurveda and Siddha system of medicine in India. Almost all the parts of the plant, such as flowers, leaves, seeds, barks, and roots have been reported for their medicinal uses. Traditionally, it has been used in the treatment of diabetes, asthma, rheumatism, dysentery, skin disease, and metabolic disorders. The principle phytochemicals in Senna auriculata (L.) Roxb. are alkaloids, anthraquinone, flavone glycosides, sugar, saponins, phenols, terpenoids, flavonoids, tannins, steroids, palmitic acid, linoleic acid, benzoic acid 2-hydroxyl methyl ester, 1-methyl butyl ester, resorcinol, α-tocopherol-β-D-mannosidase, epicatechin, ferulic acid, quercetin-3-O-rutinoside, quercetin, proanthocyanidin B1. The extracts from its different parts and their isolated compounds possess a wide range of pharmacological activities such as antidiabetic, antioxidant, anti-inflammatory, antihyperlipidemic, hepatoprotective, nephroprotective, cardioprotective, anti-atherosclerotic, anticancer, antimutagenic, antimicrobial, antiulcer, antipyretic, anthelmintic, immunomodulatory, antifertility, anti-venom, and anti-melanogenesis. The toxicological findings from preclinical studies ensured the safety of the plant, but comprehensive clinical studies are required for the safety and efficacy of the plant in humans. The current review article aimed to provide up-to-date information about Senna auriculata (L.) Roxb. covering its ethnomedicinal, phytochemical, pharmacological, and toxicological aspects with special emphasis on its clinical implications in diabetes.

Phytomedicines Used for Diabetes Mellitus in Ghana: A Systematic Search and Review of Preclinical and Clinical Evidence

BACKGROUND

Available data indicate that diabetes mellitus leads to elevated cost of healthcare. This imposes a huge economic burden on households, societies, and nations. As a result many Ghanaians, especially rural folks, resort to the use of phytomedicine, which is relatively less expensive. This paper aims at obtaining information on plants used in Ghana to treat diabetes mellitus, gather and present evidence-based data available to support their uses and their mechanisms of action, and identify areas for future research.

METHOD

A catalogue of published textbooks, monographs, theses, and peer-reviewed articles of plants used in Ghanaian traditional medicine between 1987 and July 2018 for managing diabetes mellitus was obtained and used.

RESULTS

The review identified 76 plant species belonging to 45 families that are used to manage diabetes mellitus. Leaves were the part of the plants frequently used for most preparation (63.8%) and were mostly used as decoctions. Majority of the plants belonged to the Euphorbiaceae, Lamiaceae, Asteraceae, and Apocynaceae families. Pharmacological data were available on 23 species that have undergone in vitro studies. Forty species have been studied using in vivo animal models. Only twelve plants and their bioactive compounds were found with data on both preclinical and clinical studies. The records further indicate that medicinal plants showing antidiabetic effects did so via biochemical mechanisms such as restitution of pancreatic β-cell function, improvement in insulin sensitivity by receptors, stimulating rate of insulin secretion, inhibition of liver gluconeogenesis, enhanced glucose absorption, and inhibition of G-6-Pase, α-amylase, and α-glucosidase activities.

CONCLUSION

This review contains information on medicinal plants used to manage diabetes mellitus, including their pharmacological properties and mechanisms of action as well as models used to investigate them. It also provides gaps that can form the basis for further investigations and development into useful medications for effective treatment of diabetes mellitus.

MD-1, a poly herbal formulation indicated in diabetes mellitus ameliorates glucose uptake and inhibits adipogenesis - an in vitro study

Background

Type 2 Diabetes (T2D) is a polygenic disease requiring a multipronged therapeutic approach. In the current scenario, the use of polyherbals is increasing among the diabetics. MD-1, a poly herbal formulation is constituted as a mixture of six popular anti diabetic herbs, used in the management of Diabetes mellitus (DM). The physicochemical, biochemical and in vitro efficacy studies have been carried out to ascertain the possible mechanisms underlying the anti-diabetic action of MD-1.

Methods

MD-1 was evaluated for residual toxins as per Ayurvedic Pharmacoepia of India (API) procedures. The hydro alcoholic extract of the formulation (HAEF) was evaluated for anti oxidant activity against 2, 2-diphenyl-1-picrylhydrazil (DPPH) and nitric oxide radicals in vitro. The effect of HAEF on carbohydrate digestive enzymes α-glucosidase and α-amylase was studied using biochemical assays. HAEF was studied for its glucose lowering potential in L6 myotubes and 3T3L1 preadipocytes, using 2-deoxy-D-[1-³H] glucose (2-DG) uptake assay. Effect of MD-1 on adipogenesis was evaluated in 3T3L1 adipocytes using oil O red staining. The effect of HAEF on mRNA expression of peroxisome proliferator activated receptor gamma (PPARγ) and glucose transporter 4 (GLUT4) in 3T3L1 adiocytes was investigated by reverse transcriptase polymerase chain reaction (RT-PCR). Statistical analysis was performed by student t-test, ANOVA.

Results

Residual toxins present within the API limits and HAEF demonstrated strong antioxidant potential and significantly inhibited the α-glucosidase (IC₅₀ 63.6 ± 0.46 μg/mL) and α-amylase (IC₅₀ 242.81 ± 1.26 μg/mL) activity. HAEF significantly (p < 0.05) enhanced the insulin stimulated glucose uptake in both the cell lines studied. Unlike standard pioglitazone (PGZ), HAEF modulated the mRNA expression of PPARγ and GLUT4 (p < 0.0001) in 3T3L1 adipocytes, without inducing adipogenesis.

Conclusion

Physicochemical parameters established in the study may serve as reference standards in regular quality control. Absence of residual toxins underpins the safety. The enhanced glucose uptake and favorable modulation of insulin sensitivity through a plausible weak PPARγ agonism is similar to the distinct PPARγ activation pattern of several reported natural compound agonists. The differential binding modes of such dynamic combinatorial ligands within the formulation unlike synthetic ligands like thiozolidinediones (TZD) can be linked to the safe mitigation of diabetic complications by MD-1.

Evaluation of phenolic content and antioxidant potency in various parts of Cassia auriculata L.: a traditionally valued plant

Presence of polyphenolic content in various part of the plant exhibit wide pharmacological activities including antioxidant activity. The present study was designed to evaluate the phenolic contents (total phenols, flavonoid and tannins) and antioxidant properties of ethanolic extracts of flower, leaf, pod, bark and root obtained from Cassia auriculata. Ethanolic extracts of various parts of C. auriculata obtained by sonication extraction techniques are studied for their phenolic contents and DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging assay as well as total antioxidant assays using UV visible spectrophotometer. Among the various parts of the plant studied, bark showed significant content of phenolics, flavonoids and tannins followed by the root, leaf, flower and pod. Even bark extract exhibited highest antioxidant capacity in DPPH assay followed by root, leaf, flower and pod with a value of 766.7, 679.3, 644.9, 572.5 and 474.7 mg vitamin C equivalent antioxidant capacity (mg VCEAC)/sample, respectively. In addition, mg VCEAC values obtained from the total antioxidant assay was in the increasing order of bark > root > leaf > flower > pod. Moreover, a strong correlation was also found between phenolic contents and antioxidant values indicating their influence in the found antioxidant activity, hence the bark extract can be employed as an ideal candidate for herbal based pharmaceutical product. Results of the present study also emphasize variation in the chemical composition as well as biological activity ensuring the importance of proper selection of particular part of the plant to evaluate their therapeutic potency.

Metabolic effects of sulforaphane oral treatment in streptozotocin-diabetic rats

Diabetes has reached epidemic levels in the whole world, and the use of bioactive compounds that may have the capacity to prevent and treat diabetes is of great interest. Sulforaphane (SFN) is a compound which is found in cruciferous vegetables and that acts as both a potent antioxidant and regulator of gene expression. The aim of this study was to evaluate the effect of SFN in diabetes induced by streptozotocin (STZ). Male Wistar rats were gavaged with water or 0.1, 0.25, or 0.5 mg/kg of SFN before an injection of STZ (80 mg/kg). Animals treated with SFN showed fasting glycemia, insulin sensitivity, and hepatic glycogen concentrations, similar to the control group (nondiabetic), and different from the diabetic group. Diabetic animals also presented elevated levels of serum triacylglycerols (TAG), urea, and creatinine, and all SFN doses were able to reverse these alterations. However, the same doses of SFN accentuated alterations in total cholesterol, alanine, and aspartate aminotransferase levels, and had no effect on hepatic TAG, HDL cholesterol, and uptake of 2-deoxy glucose in adipose tissue and soleum muscle. Based on the effects inferred by the present data, SFN presented some positive effects against diabetes induction, although the impairment of hepatic function and cholesterol levels were aggravated after treatment with the compound.

Aqueous extract of Liriope platyphylla, a traditional Chinese medicine, significantly inhibits abdominal fat accumulation and improves glucose regulation in OLETF type II diabetes model rats

Liriope platyphylla is a medical herb that has long been used in Korea and China to treat cough, sputum, neurodegenerative disorders, obesity, and diabetes. The aims of this study were to determine the antidiabetic and antiobesity effects of aqueous extract of L. platyphylla (AEtLP) through glucose and lipid regulation in both pre-diabetes and obesity stage of type II diabetes model. Two concentrations of AEtLP were orally administrated to OLETF (Otsuka Long-Evans Tokushima Fatty) rats once a day for 2 weeks, after which changes in glucose metabolism and fat accumulation were measured. Abdominal fat mass dramatically decreased in AEtLP-treated OLETF rats, whereas glucose concentration slightly decreased in all AEtLP-treated rats. However, compared to vehicle-treated OLETF rats, only AEtLP10 (10% concentration)-treated OLETF rats displayed significant induction of insulin production, whereas AEtLP5 (5% concentration)-treated OLETF rats showed a lower level of insulin. Although serum adiponectin level increased in only AEtLP5-treated rats, significant alteration of lipid concentration was detected in AEtLP5-treated OLETF rats. Expression of Glut-1 decreased in all AEtLP-treated rats, whereas Akt phosphorylation increased only in AEtLP10-treated OLETF rats. Furthermore, the pattern of Glut-3 expression was very similar with that of Glut-1 expression, which roughly corresponded with the phosphorylation of c-Jun N-teminal kinase (JNK) and p38 in the mitogen-activated protein kinase pathway. Therefore, these findings suggest that AEtLP should be considered as a therapeutic candidate during pre-diabetes and obesity stage capable of inducing insulin secretion from pancreatic β-cells, glucose uptake in liver cells, as well as a decrease in fat and lipid accumulation.

Interaction of herbs and glibenclamide: a review

Herbs and herbal products are considered to be safer and people mix it often with the oral hypoglycemic agent in diabetes therapy. But numerous reports say that every combination of herbs and drugs is not safe. Some combinations may be beneficial and some may be harmful also. So before taking any herbal remedies with oral hypoglycemic agent, patient should consult physician. In this paper we are summarizing the reports available on the interaction of herbal remedies to one of the oral hypoglycemic agents (glibenclamide) and categorizing the effect of the combination is beneficial and harmful.

Antimalarial activities of medicinal plants traditionally used in the villages of Dharmapuri regions of South India

ETHNOPHARMACOLOGICAL RELEVANCE

An ethnopharmacological investigation of medicinal plants traditionally used to treat diseases associated with fevers in Dharmapuri region of South India was undertaken. Twenty four plants were identified and evaluated for their in vitro activity against Plasmodium falciparum and assessed for cytotoxicity against HeLa cell line.

AIM OF THE STUDY

This antimalarial in vitro study was planned to correlate and validate the traditional usage of medicinal plants against malaria.

MATERIALS AND METHODS

An ethnobotanical survey was made in Dharmapuri region, Tamil Nadu, India to identify plants used in traditional medicine against fevers. Selected plants were extracted with ethyl acetate and methanol and evaluated for antimalarial activity against erythrocytic stages of chloroquine (CQ)-sensitive 3D7 and CQ-resistant INDO strains of Plasmodium falciparum in culture using the fluorescence-based SYBR Green I assay. Cytotoxicity was determined against HeLa cells using MTT assay.

RESULTS

Promising antiplasmodial activity was found in Aegle marmelos [leaf methanol extract (ME) (IC(50)=7 μg/mL] and good activities were found in Lantana camara [leaf ethyl acetate extract (EAE) IC(50)=19 μg/mL], Leucas aspera (flower EAE IC(50)=12.5 μg/mL), Momordica charantia (leaf EAE IC(50)=17.5 μg/mL), Phyllanthus amarus (leaf ME IC(50)=15 μg/mL) and Piper nigrum (seed EAE IC(50)=12.5 μg/mL). The leaf ME of Aegle marmelos which showed the highest activity against Plasmodium falciparum elicited low cytotoxicity (therapeutic index>13).

CONCLUSION

These results provide validation for the traditional usage of some medicinal plants against malaria in Dharmapuri region, Tamil Nadu, India.

Consensus of local knowledge on medicinal plants among traditional healers in Mayiladumparai block of Theni District, Tamil Nadu, India

AIM OF THE STUDY

The role of ethnobotany in drug discovery is huge but there are criticisms over such studies due to their qualitative nature. The present study is aimed at quantitatively abstracting the medicinal plant knowledge of the healers trained in traditional ways, in Mayiladumparai block of Theni District, Tamil Nadu, India.

MATERIALS AND METHODS

The interviews and field observations were carried out in all the 18 village panchayaths from January to June 2010, consisting of 148 field days. The interviews were conducted with 80 traditional healers, after obtaining prior informed consent. Successive free listing was used to interview the informants. The informant consensus factor (F(ic)) was calculated to estimate the use variability of medicinal plants. Fidelity index and Cultural importance index were also calculated to analyze the data.

RESULTS

This study recorded the ethno-medicinal usage of 142 ethno-species belonging to 62 families that were used to prepare 504 formulations. Jaundice had the highest F(ic) value than all the illness categories studied. Phyllanthus spp. was the highly cited medicinal plant to treat jaundice and had high fidelity index value. This was followed by Senna angustifolia and Terminalia chebula as laxatives. The highly cited medicinal plants in each group with high F(ic) value were Pongamia pinnata (antiseptic), Aerva lanata (antidote and snakebite), Blepharis maderaspatensis (cuts and wounds), Abutilon indicum (hemorrhoids), Ruta graveolens (spiritual medicine), Ocimum tenuiflorum (cough), and Solanum trilobatum (pulmonary ailments). Phyllanthus spp., was the most culturally significant species according to this index, followed by Borassus flebellifer.

CONCLUSION

The process of drug discovery has become highly expensive and post-approval and post-marketing withdrawal of drugs is continuing. In such scenario, reverse pharmacology is considered an attractive option. The medicinal plants enumerated in this study with high number of citations and high F(ic) values for illness categories might give some useful leads for further biomedical research.