Hypoglycemic and hypocholesterolemic activities of the aqueous leaf and seed extract of Phyllanthus amarus in mice

Treatment with Terminalia chebula Extract Reduces Insulin Resistance, Hyperglycemia and Improves SIRT1 Expression in Type 2 Diabetic Rats

BACKGROUND

Terminalia chebula Retz., Family Combretaceae (T. chebula) is one of the important plants mentioned in Ayurveda, a traditional system of medicine. The present work was designed to study the effect of the aqueous extract of T. chebula fruits in type 2 diabetic rats.

METHODS

The aqueous extract of the fruits was prepared by the double maceration technique. The extract was subjected to HPTLC analysis, which showed the presence of ellagic acid and gallic acid. Type 2 diabetes was induced in rats with a low dose of Streptozotocin (35 mg/kg) after administering a high-fat diet for fourteen days. Diabetic animals were treated with 500 and 1000 mg/kg of aqueous extract of T. chebula fruits for six weeks.

RESULTS

Diabetic rats showed a significantly (511.7 ± 17.6) (p < 0.001) high plasma glucose level compared to the normal group (106 ± 3.358). The T. chebula treatment group showed a significant (p < 0.001) reduction in plasma glucose at 500 mg/kg (394.3 ± 10.35) and 1000 mg/kg (368.6 ± 30.08) doses when compared with the diabetic control group. Treatment with aqueous extract significantly reduced lipid parameters in diabetic animals when compared to the animals in the diabetic control group. Treatment with extract at a dose of 500 mg/kg and 1000 mg/kg showed a significant reduction in AST (p < 0.01, p < 0.001) when compared with diabetic control rats. Treatment with extract significantly reduced ALT at 500 mg/kg (p < 0.05) and 1000 mg/kg (p < 0.001) doses when compared with diabetic control rats. The extract treatment improved insulin sensitivity and insulin sensitivity index (ISI) and significantly decreased HOMR-IR. Treatment with T. chebula aqueous extract at 1000 mg/kg significantly increased the level of GSH (p < 0.05) when compared to diabetic control rats. T. chebula treatment at 1000 mg/kg significantly increased levels of CAT (p < 0.01). Histopathology of pancreatic tissue revealed that the extract has a protective effect against the damage caused by hyperglycemia. Immunohistochemistry of pancreatic tissue showed increased expression of SIRT1 in diabetic animals treated with the extract.

CONCLUSIONS

The results of the present study indicate that the extract of T. chebula has significant effects in the management of type 2 diabetes.

An insight into the potent medicinal plant Phyllanthus amarus Schum. and Thonn

Phyllanthus amarus Schum. and Thonn., a globally distributed herb is known for its several therapeutic potentials. P. amarus has a long history of use in the traditional system of medicine for over 2000 years owing to its wide array of secondary metabolites that confer significant medicinal attributes. Research on various aspects including ethnobotany, phytochemistry to bioactivity, or pharmacological studies has been conducted over the past several decades on this potent herb. P. amarus extracts have shown a broad range of pharmacological activities like hepatoprotective, antioxidant, antiviral, antimicrobial, antidiabetic, anti-inflammatory, anticancer, antimalarial, nephroprotective, diuretic, and several other properties. The present review compiles and covers literature and research of several groups across past decades to date and focuses on how the therapeutic significance of this plant can be further explored for future research either as herbal formulations, alternative medicine, or in the pharmaceutical industry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13237-022-00409-z.

Restoration of Hepatic and Intestinal Integrity by Phyllanthus amarus Is Dependent on Bax/Caspase 3 Modulation in Intestinal Ischemia-/Reperfusion-Induced Injury

Ethnopharmacological relevance: Oxidative stress is a key player in intestinal ischemia/reperfusion (I/R) injury (IIRI) with a tendency to trigger systemic inflammatory response, resulting in progressive distal organ injury. To date, the role of Bax/caspase 3 signaling in IIRI has not been reported. Furthermore, the discovery of a safe and effective drug remains pertinent in improving the outcome of IIRI. Therefore, this study investigated the role of Bax/caspase 3 signaling in intestinal I/R-induced intestinal and hepatic injury. In addition, the protective effect and possible associated mechanism of action of methanolic Phyllanthus amarus leaf extract (PA) against intestinal I/R-induced intestinal and hepatic injury were evaluated. Materials and methods: Fifty male Wistar rats were randomized into five groups (n = 10). The sham-operated group was received 0.5 mL of distilled water for seven days prior to the sham surgery, while the IIRI, febuxostat (FEB) + IIRI, low-dose PA (LDPA) + IIRI, and high-dose PA (HDPA) + IIRI groups underwent the I/R procedure. In addition to the procedure, IIRI, FEB + IIRI, LDPA + IIRI, and HDPA + IIRI received 0.5 mL of distilled water, 10 mg/kg of febuxostat, 200 mg/kg of PA, and 400 mg/kg of PA, respectively, for seven days prior to the I/R procedure. Results: Administration of methanolic Phyllanthus amarus leaf extracts attenuated the intestinal I/R-induced rise in intestinal and hepatic injury markers, malondialdehyde, nitric oxide, TNF-α, IL-6, and myeloperoxidase activities. In addition, Phyllanthus amarus ameliorated I/R-induced suppression of reduced glutathione, thiol and non-thiol proteins, and superoxide dismutase, catalase, and glutathione peroxidase activities in intestinal and hepatic tissues. These were coupled with the suppression of I/R-induced bacterial translocation, downregulation of I/R-induced activation of Bax/caspase 3 signaling, and improvement of I/R-induced distortion of intestinal and hepatic histoarchitecture by Phyllanthus amarus. Conclusion: Methanolic Phyllanthus amarus leaf extract protects against intestinal and hepatic injuries associated with intestinal I/R by suppressing oxidative-stress-mediated activation of Bax/caspase 3 signaling. The beneficial effects of Phyllanthus amarus may be ascribed to its constituent bioactive molecules, especially tannins, anthocyanin, alkaloids, and phenolics.

Pengaruh Kombinasi Metformin dan Ekstrak Air Meniran (Phyllanthus niruri Linn.) terhadap Perbaikan Status Obesitas Tikus Sprague dawley Jantan

Latar Belakang: Perubahan gaya hidup dan pola makan menyebabkan tingginya angka kejadian obesitas di seluruh dunia yaitu 13% padat tahun 2016. Perbaikan status obesitas dapat dilakukan melalui jalur farmakologik ataupun non farmakologik. Metformin dan meniran (Phyllanthus niruri Linn.) mempunyai fungsi untuk menurunkan penyerapan asupan makanan.Tujuan: menganalisis pengaruh kombinasi metformin dan ekstrak air meniran (Phyllanthus niruri Linn.) terhadap perbaikan status obesitas tikus Sprague Dawley jantan.Metode: multigroup time series design.  Dua puluh empat ekor tikus dibuat obesitas dengan cara diberi pakan tambahan lemak sapi cair dan fruktosa terhadap pakan dasar AIN93G selama 5 minggu. Obesitas ditentukan dengan indeks Lee > 300. Sampel dikelompokkan menjadi 4 kelompok, kelompok 1 diberi metformin 45 mg/kg BB/hari, kelompok 2 diberi ekstrak air meniran 400 mg/kg BB/hari, kelompok 3 diberi kombinasi keduanya, dan kelompok 4 kontrol.Hasil: Selama penelitian ada perbedaan berat pakan dan asupan kalori  pada setiap kelompok perlakuan. Setelah 28 hari perlakuan ada perbedaan kenaikan berat badan dan perubahan indeks Lee antara ketiga kelompok perlakuan (ρ < 0,05), walaupun indeks Lee > 300.Kesimpulan: pemberian kombinasi ekstrak air meniran dan metformin dapat mengendalikan kenaikan berat badan dan menurunkan indeks Lee.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

Phyllanthus amarus prevents LPS-mediated BV2 microglial activation via MyD88 and NF-κB signaling pathways

BACKGROUND

Phyllanthus amarus has been shown to attenuate lipopolysaccharide (LPS)-induced peripheral inflammation but similar studies in the central nervous system are scarce. The aim of the present study was to investigate the neuroprotective effects of 80% ethanol extract of P. amarus (EPA) in LPS-activated BV2 microglial cells.

METHODS

BV2 microglial cells c for 24 h, pre-treated with EPA for 24 h prior to LPS induction for another 24 h. Surface expression of CD11b and CD40 on BV2 cells was analyzed by flow cytometry. ELISA was employed to measure the production of pro-inflammatory mediators i.e. nitric oxide (NO) and tumor necrosis factor (TNF)-α. Western blotting technique was used to determine the expression of inducible nitric oxide synthase (iNOS), myeloid differentiation protein 88 (MYD88), nuclear factor kappa B (NF-κB), caspase-1, and mitogen activated protein kinase (MAPK).

RESULTS

Qualitative and quantitative analyses of the EPA using a validated ultra-high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method indicated the presence of phyllanthin, hypophyllanthin, niranthin, ellagic acid, corilagin, gallic acid, phyltetralin, isolintetralin and geraniin. EPA suppressed the production of NO and TNFα in LPS-activated BV2 microglial cells. Moreover, EPA attenuated the expression of MyD88, NF-κB and MAPK (p-P38, p-JNK and p-ERK1/2). It also inhibited the expression of CD11b and CD40. EPA protected against LPS-induced microglial activation via MyD88 and NF-κB signaling in BV2 microglial cells.

CONCLUSIONS

EPA demonstrated neuroprotective effects against LPS-induced microglial cells activation through the inhibition of TNFα secretion, iNOS protein expression and subsequent NO production, inhibition of NF-κB and MAPKs mediated by adapter protein MyD88 and inhibition of microglial activation markers CD11b and CD40.

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.

Pharmacological and polyphenolic profiles of Phyllanthus phillyreifolius var. commersonii Müll. Arg: An unexplored endemic species from Mauritius

Phyllanthus phillyreifolius var. commersonii Müll. Arg is an endemic plant of Mauritius. To date, no study has been performed concerning its polyphenolic profile and pharmacological properties. In this study, a decoction (water), ethyl acetate and methanol extracts of the aerial parts of P. phillyreifolius, obtained from different extraction procedures (maceration and Soxhlet), were studied for antibacterial, antioxidant, anticancer, and enzyme inhibitory properties along with their polyphenolic profile. The ethyl acetate macerated extract showed high antibacterial activity against B. cereus (MIC = 0.293 mg/mL) and E. coli (MIC = 0.417 mg/mL) while S. epidermidis was most susceptible to the ethyl acetate-Soxhlet extract (MIC = 0.521 mg/mL). The methanol-Soxhlet extract displayed the most potent cupric and ferric reducing power, and metal chelating effect, while the macerated methanolic extract was the most effective DPPH and ABTS scavenger, and BChE inhibitor. Only the ethyl acetate-Soxhlet extract exhibited α-glucosidase inhibition. All extracts exhibited a strong anti-tyrosinase activity, which was further investigated by molecular docking and molecular dynamic. After 48 h exposure to the extracts for HeLa cell lines, the ethyl acetate-Soxhlet extract showed the highest inhibition (IC₅₀ = 533.1 μg/mL) while the decoction extract was more cytotoxic to MDA-MB-231 cells (IC₅₀ = 337.4 μg/mL). Treatment of cancer cell lines with all P. phillyreifolius extracts resulted in a time-dependent reduction of cell viability for HeLa and dose-and time-dependent reduction for MDA-MB-231. Gene expression ratio of Bcl-2 to Bax was higher for all Soxhlet-extracts. Total phenolics (TPC) and flavonoids (TFC) content were highest in the decoction and methanol-Soxhlet extract, respectively (122.43 mg GAE/g extract and 31.28 mg RE/g extract, respectively). The extracts were abundant in ellagitannins, although phenolic acids and flavonoids were also detected. Granatin B was detected for the first time in Phyllanthus species. Overall, the aerial parts of P. phillyreifolius exemplify a potent reservoir of bioactive phytochemicals for therapeutic applications.

The acute diuretic effect of an ethanolic fraction of Phyllanthus amarus (Euphorbiaceae) in rats involves prostaglandins

Background

Phyllanthus amarus (Schum & Thonn), a plant belonging to the family of Euphorbiaceae is used in Ivorian traditional medicine to treat cardiovascular disorders such as hypertension. However, although this plant has been described as a diuretic agent, the underlying mechanism remains unclear. Therefore, the aim of the present study was to investigate the mechanism action of diuretic effects of an ethanolic fraction of Phyllanthus amarus (EFPA) in rats.

Methods

Effects of EFPA on urinary excretion were carried out for doses ranging from 5 to 80 mg/kg given by intraperitoneal injection (i.p.) and compared with that induced by furosemide (5 mg/kg) after 8 h. Thereafter, the diuretic activity of EFPA was also evaluated in the presence of indomethacin (5 mg/kg, i.p.) in order to determine the involvement of prostaglandins, after 24 h.

Results

Between 5 and 80 mg/kg, EFPA induced a significant urinary excretion. The profile of urinary excretion showed that after 2 h, the highest dose of 80 mg/kg induced a urinary volumetric excretion (UVE), which was similar to that induced by furosemide. After 24 h, EFPA at 10 mg/kg increased significantly UVE, Na⁺ (43 mEq) and Cl^¯ (97 mEq) urinary excretions without promoting kaliuresis. In rats pretreated with indomethacin, the urinary excretion and the natriuretic response of EFPA were significantly reduced.

Conclusion

Altogether, this study has shown that EFPA promotes a significant urinary excretion of water and Na⁺, confirming its diuretic activity. Moreover, the increased diuresis could be attributed, at least in part, to the involvement of prostaglandins.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2158-0) contains supplementary material, which is available to authorized users.

Beneficial Effects of Phyllanthus amarus Against High Fructose Diet Induced Insulin Resistance and Hepatic Oxidative Stress in Male Wistar Rats

Insulin resistance (IR) is a characteristic feature of obesity, type 2 diabetes mellitus, and cardiovascular diseases. Emerging evidence suggests that the high-fructose consumption is a potential and important factor responsible for the rising incidence of IR. The present study investigates the beneficial effects of aqueous extract of Phyllanthus amarus (PAAE) on IR and oxidative stress in high-fructose (HF) fed male Wistar rats. HF diet (66% of fructose) and PAAE (200 mg/kg body weight/day) were given concurrently to the rats for a period of 60 days. Fructose-fed rats showed weight gain, hyperglycemia, hyperinsulinemia, impaired glucose tolerance, impaired insulin sensitivity, dyslipidemia, hyperleptinemia, and hypoadiponectinemia (P < 0.05) after 60 days. Co-administration of PAAE along with HF diet significantly ameliorated all these alterations. Regarding hepatic antioxidant status, higher lipid peroxidation and protein oxidation, lower reduced glutathione levels and lower activities of enzymatic antioxidants, and the histopathological changes like mild to severe distortion of the normal architecture as well as the prominence and widening of the liver sinusoids observed in the HF diet-fed rats were significantly prevented by PAAE treatment. These findings indicate that PAAE is beneficial in improving insulin sensitivity and attenuating metabolic syndrome and hepatic oxidative stress in fructose-fed rats.

Inhibitory effects of compounds from Phyllanthus amarus on nitric oxide production, lymphocyte proliferation, and cytokine release from phagocytes

Standardized extract of Phyllanthus amarus has previously been shown to have a strong inhibitory effect on phagocytic activity of human neutrophils. The current study was carried out to evaluate the effects of constituents of the extract of P. amarus on nitric oxide (NO) production as well as lymphocyte proliferation and cytokine release from phagocytes. Three compounds, ethyl 8-hydroxy-8-methyl-tridecanoate, 7β,19α dihydroxy-urs-12-ene, and 1,7,8-trihydroxy-2-naphtaldehyde, together with seven known compounds were isolated from the whole plant of P. amarus. The isolated compounds and reference standards, ie, gallic acid, ellagic acid, corilagin, and geraniin, which were quantitatively analyzed in the extracts, were evaluated for their effects on immune cells. Among the compounds tested, the lignans, especially phyltetralin and phyllanthin, showed strong inhibition on lymphocyte proliferation with half maximal inhibitory concentration (IC₅₀) values of 1.07 μM and 1.82 μM, respectively. Ethyl 8-hydroxy-8-methyl-tridecanoate and 1,7,8-trihydroxy-2-naphtaldehyde exhibited strong inhibition on nitric oxide production with IC₅₀ values of 0.91 μM and 1.07 μM, respectively. Of all the compounds, corilagin was the strongest inhibitor of tumor necrosis factor-α release with an IC₅₀ value of 7.39 μM, whereas geraniin depicted the strongest inhibitory activity on interleukin-1β release with an IC₅₀ value of 16.41 μM. The compounds constituting the extract of P. amarus were able to inhibit the innate immune response of phagocytes at different steps.

Antioxidant plants and diabetes mellitus

The incidence of diabetes mellitus (DM) is increasing rapidly and it is expected to increase by 2030. Other than currently available therapeutic options, there are a lot of herbal medicines, which have been recommended for its treatment. Herbal medicines have long been used for the treatment of DM because of the advantage usually having no or less side-effects. Most of these plants have antioxidant activities and hence, prevent or treat hard curable diseases, other than having the property of combating the toxicity of toxic or other drugs. In this review other than presenting new findings of DM, the plants, which are used and have been evaluated scientifically for the treatment of DM are introduced.

Self-assembly of glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria

Glycinin nanoparticles for delivery of phenolic compounds from Phyllanthus urinaria.

The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system.

MATERIALS AND METHODS

Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. 'Diabetes' and 'Nigeria' were used as keywords for the primary searches; and then 'Plant name - accepted or synonyms', 'Constituents', 'Drug interaction' and/or 'Toxicity' for the secondary searches.

RESULTS

The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs.

CONCLUSION

This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb-drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided.

Cnidoscolus chayamansa Mc Vaugh, an important antioxidant, anti-inflammatory and cardioprotective plant used in Mexico

ETHNOPHARMACOLOGICAL RELEVANCE

Cnidoscolus chayamansa Mc Vaugh (Euphorbiaceae) is commonly known as 'chaya' in Central America. In South East Mexico, because of its high nutritional values, is an important part of the diet of many indigenous communities. Chaya is also used as a traditional remedy for the treatment of diabetes, rheumatism, gastrointestinal disorders and inflammation-related diseases. Although Cnidoscolus chayamansa is one of most used and valued medicinal plants, only few studies on documenting its pharmacological properties can be found.

MATERIALS AND METHODS

Dried leaves of Cnidoscolus chayamansa were subjected to a successive maceration using Hex, EtOAc and EtOH. The antioxidant activities of the extracts were tested using the DPPH radical scavenging, Ferric reducing/antioxidant power and total phenolic content assays. To determine the anti-inflammatory activity, the TPA-induced mouse ear edema and the carrageenan-induced mouse paw edema assays were used. The cardioprotective effects of the EtOH extract was determined using the ischemia/reperfusion (I/R) rat model. Finally, the acute toxicity was determined using Lorke's method.

RESULTS

The results showed a similar anti-inflammatory activity (≈30%) for all extracts but only the EtOAc extract showed relevant activity when applied intraperitoneally. When tested for their antioxidant activity none of the extracts showed a significant activity suggesting that the antinflammatory activity is not related to a direct free radical scavenging of the extracts. Additionally, the EtOH extract showed a strong cardioprotective effect at 500mg/kg when given orally. Both the EtOAc and the EtOH extract have a LD50 >5g/kg, confirming their safety in acute oral administration.

CONCLUSIONS

All these results are relevant for a better understanding of the therapeutic used of Cnidoscolus chayamansa in the Mexican traditional medicine and highlights its cardioprotective potential.

Inhibitory Effects of Standardized Extracts of Phyllanthus amarus and Phyllanthus urinaria and Their Marker Compounds on Phagocytic Activity of Human Neutrophils

The standardized methanol extracts of Phyllanthus amarus and P. urinaria, collected from Malaysia and Indonesia, and their isolated chemical markers, phyllanthin and hypophyllanthin, were evaluated for their effects on the chemotaxis, phagocytosis and chemiluminescence of human phagocytes. All the plant extracts strongly inhibited the migration of polymorphonuclear leukocytes (PMNs) with the Malaysian P. amarus showing the strongest inhibitory activity (IC50 value, 1.1  µ g/mL). There was moderate inhibition by the extracts of the bacteria engulfment by the phagocytes with the Malaysian P. amarus exhibiting the highest inhibition (50.8% of phagocytizing cells). The Malaysian P. amarus and P. urinaria showed strong reactive oxygen species (ROS) inhibitory activity, with both extracts exhibiting IC50 value of 0.7  µ g/mL. Phyllanthin and hypophyllanthin exhibited relatively strong activity against PMNs chemotaxis, with IC50 values slightly lower than that of ibuprofen (1.4  µ g/mL). Phyllanthin exhibited strong inhibitory activity on the oxidative burst with an IC50 value comparable to that of aspirin (1.9  µ g/mL). Phyllanthin exhibited strong engulfment inhibitory activity with percentage of phagocytizing cells of 14.2 and 27.1% for neutrophils and monocytes, respectively. The strong inhibitory activity of the extracts was due to the presence of high amounts of phyllanthin and hypophyllanthin although other constituents may also contribute.

The leaf and seed aqueous extract of Phyllanthus amarus improves insulin resistance diabetes in experimental animal studies

ETHNOPHARMACOLOGICAL RELEVANCE

Amongst the Yoruba tribe (Southwest Nigeria), water decoction of the leaf and seed of Phyllanthus amarus Schum. and Thonn. is reputably used for the local management of diabetes mellitus, obesity and hyperlipidemia.

AIM OF THE STUDY

The present study seeks to evaluate the effectiveness and elucidate mechanism(s) of action of the aqueous leaf and seed extract of Phyllanthus amarus (PAE) in normal and 10% sucrose-induced hyperglycemia and dyslipidemia as an experimental model of insulin resistance diabetes mellitus.

MATERIALS AND METHODS

In this study, the repeated oral antihyperglycemic action of 150-600 mg/kg/day of PAE was evaluated in normal and 10% sucrose-induced insulin resistance rats using indicators such as fasting blood glucose (FBG), insulin and insulin resistance indices. The extract's weight losing, antihyperlipidemic and anti-atherogenic effects were also evaluated by measuring the effect of the extract on the body weight, plasma levels of triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c) and atherogenic indices.

RESULTS

In normal rats, PAE caused significant (p<0.05, p<0.01 and p<0.001) and dose related decreases in body weight, FBG, TG, TC, LDL-c, and atherogenic indices. Repeated oral treatment with 10% sucrose drink for 30 days was associated with significant (p<0.001) weight gain, hyperglycemia, insulin resistance indices, hyperlipidemia and atherogenic indices. However, pre-treatment with PAE significantly (p<0.05, p<0.01 and p<0.001) and dose-dependently attenuated increase in any of these measured parameters.

CONCLUSIONS

Overall, results of this study showed PAE to effectively control insulin resistance DM which was mediated via improvement in insulin resistance, thus, validating its ethnomedical use in the local management of DM.

Histological effects of chronic administration of Phyllanthus amarus on the kidney of adult Wistar rat

BACKGROUND

Phyllanthus amarus is commonly used for treatment such as in gastro, urogenital diseases and infection. However, it is speculated to have some toxic effects such as renal tubular damage.

AIMS

This study was to investigate the histological effects of chronic administration of the herb on kidney of adult Wistar rats.

MATERIAL AND METHODS

Rats of both sexes (n = 24), with average weight of 200g were randomly assigned into two treatments (A and B) and control (C) groups of 8 rats each. Rats in treatment groups (A) and (B) respectively received daily administration of 400mg and 800mg of aqueous Phyllanthus amarus, per 70kg body weight for 30days through the orogastric tube. The control group received distilled water through the same route. All rats were fed with grower's mash and given water liberally. The rats were sacrificed by cervical dislocation on the thirty-first day of the experiment and the kidneys were carefully dissected out and quickly fixed in 10% formal saline for histological study.

RESULTS

The observations indicate that rats in the treated groups showed some varying degree of distortion and disruption in microanatomy of the kidney including interstitial oedema and tubular necrosis, when compared to the control section.

CONCLUSION

This report provides further evidence that medicinal use of Phyllanthus amarus has a potential adverse effect. This warrants further studies to establish or rule out any untoward side-effect of chronic renal dysfunctions.

Acute toxicity studies of aqueous leaf extract of Phyllanthus niruri

Phyllanthus niruri is a plant with medicinal properties. It is often used to treat mild malaria and the elimination of renal stones. However, studies on its toxicity are scarce. The study was carried out to determine if the aqueous leaf extract of P. niruri administered to female Sprague-Dawley rats would illicit evidence of toxicity. Fifteen female rats weighing 150–200 g were divided into 3 groups. Rats in Group 1 were given a single low dose (LD) of 2000 mg/kg b.w. of the extract by oral gavage within 24 hrs. Rats in Group 2 were given a single high dose (HD) of 5000 mg/kg b.w. of the extract by oral gavage within 24 hrs. Rats in Group 3 were not given any extract but drinking water and served as the control group (C). All the rats were observed for signs of toxidromes for 14 days. On the 15^th day, all the rats were sacrificed. Body organs were harvested for macroscopic examination. Urine and blood samples were drawn and analyzed. Hematological tests performed included full blood count and hemoglobin. Biochemical examinations included bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, albumin, globulin, alkaline phosphatse (ALP), γ-glutamyltranspeptidase (GGT), urea, and creatinine. The results of the three groups were not significantly different. Examination of the various body organs did not show any abnormality. Thus no toxicity was observed at the levels administered. The LD₅₀ of the aqueous extract is>5000 mg/kg. b.w.

Geraniin and amariin, ellagitannins from Phyllanthus amarus, protect liver cells against ethanol induced cytotoxicity

Ethanol mediated free radical generation plays an important role in the pathogenesis of liver injuries and alcoholic liver diseases. In the present study two ellagitannins namely geraniin and amariin isolated from Phyllanthus amarus were examined for their ability to protect mouse liver slices against ethanol induced toxicity and possible mechanism of its protection. Oxidative stress markers such as, lipid peroxidation, protein carbonyl formation, amount of 8-hydroxy-2-deoxyguanosine and antioxidant enzymes levels were measured using specific biochemical assays. Poly (ADP-ribose) polymerase (PARP), Bax and Bcl2 were checked to assess the induction of apoptosis using western blots. The results showed that geraniin and amariin protected mouse liver slices against ethanol induced cytotoxicity. Both compounds inhibited oxidation of lipid, protein and formation of 8-hydroxy-2-deoxyguanosine, all of which were found to be elevated on exposure to ethanol. These compounds restored the antioxidant enzymes altered on ethanol exposure. Compounds also inhibited the cleavage of PARP and bax and restored Bcl2, induced on exposure to ethanol. In summary, both ellagitannins effectively protected mouse liver slices against ethanol induced cytotoxicity and apoptosis by reducing oxidative damage to biological molecules and modulating Bax/Bcl-2 ratio respectively, thus minimizing liver injury.

Effects of Phyllanthus amarus on the pharmacokinetics of midazolam and cytochrome P450 activities in rats

Phyllanthus amarus, a commonly used medicinal herb, was investigated for possible herb-drug interactions. The effect on CYP3A-mediated drug metabolism in rats after single dose administration of P. amarus extract was investigated using midazolam (MDZ) as a probe substrate. The effect of multiple dose administration of P. amarus extract on activity and expression of various CYP isoforms were studied. Oral administration of P. amarus extract (800 mg/kg) 1 h before oral MDZ increased the C(max) and AUC(0--∞) of MDZ by 3.9- and 9.6-fold and decreased the clearance by 12%, but did not alter the pharmacokinetics of intravenous MDZ. Daily administration of P. amarus extract (200 or 800 mg/kg/day) for 15 days in rats increased the activity and expression of CYP3A and CYP2B1/2. In contrast, the activities and expressions of CYP1A, CYP2C and CYP2E1 were not significantly changed. The dual effects of P. amarus extract on CYP enzymes were demonstrated. Single dose administration of the extract increased oral bioavailability of MDZ through inhibition of intestinal CYP3A whereas repeated administration of the extract slightly induced hepatic CYP3A and CYP2B1/2 in rats, which suggested that herb-drug interactions by P. amarus may potentially occur via CYP3A and 2B.

Phyllanthus amarus: ethnomedicinal uses, phytochemistry and pharmacology: a review

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus amarus Schum. & Thonn. belongs to the family Euphorbiaceae is a small herb well known for its medicinal properties and widely used worldwide. P. amarus is an important plant of Indian Ayurvedic system of medicine which is used in the problems of stomach, genitourinary system, liver, kidney and spleen. It is bitter, astringent, stomachic, diuretic, febrifuge and antiseptic. The whole plant is used in gonorrhea, menorrhagia and other genital affections. It is useful in gastropathy, diarrhoea, dysentery, intermittent fevers, ophthalmopathy, scabies, ulcers and wounds.

MATERIALS AND METHODS

The present review covers a literature across from 1980 to 2011. Some information collected from traditional Ayurvedic texts and published literature on ethanomedicinal uses of Phyllanthus amarus in different countries worldwide.

RESULTS

Phytochemical studies have shown the presence of many valuable compounds such as lignans, flavonoids, hydrolysable tannins (ellagitannins), polyphenols, triterpenes, sterols and alkaloids. The extracts and the compounds isolated from P. amarus show a wide spectrum of pharmacological activities including antiviral, antibacterial, antiplasmodial, anti-inflammatory, antimalarial, antimicrobial, anticancer, antidiabetic, hypolipidemic, antioxidant, hepatoprotective nephroprotective and diurectic properties.

CONCLUSION

The present review summarizes information concerning the morphology, ecology, ethnopharmacology, phytochemistry, biological activities, clinical applications and toxicological reports of P. amarus. This review aims at gathering the research work undertaken till date on this plant in order to provide sufficient baseline information for future works and commercial exploitation.

In vitro study on α-amylase inhibitory activity of an Indian medicinal plant, Phyllanthus amarus

OBJECTIVE

The objective of this study was to evaluate the α-amylase inhibitory activity of different extracts of Phyllanthus amarus against porcine pancreatic amylase in vitro.

MATERIALS AND METHODS

The plant extracts were prepared sequentially with ethanol, chloroform, and hexane. Each extract was evaporated using rotary evaporator, under reduced pressure. Different concentrations (10, 20, 40, 60, 80, and 100 μg/mL) of each extract were made by using dimethyl sulfoxide (DMSO) and subjected to α-amylase inhibitory assay using starch azure as a substrate. The absorbance was read at 595 nm using spectrophotometer. Using this method, the percentage of α-amylase inhibitory activity and IC(50)values of each extract was calculated.

RESULTS

The chloroform extract failed to inhibit α-amylase activity. However, the ethanol and hexane extracts of P. amarus exhibited appreciable α-amylase inhibitory activity with an IC50 values 36.05 ± 4.01 μg/mL and 48.92 ± 3.43 μg/mL, respectively, when compared with acarbose (IC(50)value 83.33 ± 0.34 μg/mL).

CONCLUSION

This study supports the ayurvedic concept that ethanol and hexane extracts of P. amarus exhibit considerable α-amylase inhibitory activities. Further, this study supports its usage in ethnomedicines for management of diabetes.

The antiplasmodial effect of the extracts and formulated capsules of Phyllanthus amarus on Plasmodium yoelii infection in mice

OBJECTIVE

To investigate the antiplasmodial activity of the extracts of Phyllanthus amarus (P. amarus) on Plasmodium yoelii (P. yoelii) (a resistant malaria parasite strain used in animal studies) infection in mice.

METHODS

The aqueous and ethanol extracts of the whole plant of Phyllanthus amarus was administered to Swiss albino mice at doses of 200 mg/kg/day, 400 mg/kg/day, 800 mg/kg/day and 1600 mg/kg/day and the prophylactic and chemotherapeutic effect of the extracts against P. yoelii infection in mice was investigated and compared with those of standard antimalaria drugs used in the treatment of malaria parasite infection. Acute toxicity test was carried out in mice to determine the safety of the plant extract when administered orally.

RESULTS

The results showed that the extracts demonstrated a dose-dependent prophylactic and chemotherapeutic activity with the aqueous extracts showing slightly higher effect than the ethanol extract. The antiplasmodial effects of the extracts were comparable to the standard prophylactic and chemotherapeutic drugs used in chloroquine resistant Plasmodium infection although the activity depended on the dose of the extract administered. The extracts showed prophylactic effect by significantly delaying the onset of infection with the suppression of 79% at a dose of 1600 mg/kg/day.

CONCLUSIONS

The results obtained indicate that the extracts of the whole plant of P. amarus possess repository and chemotherapeutic effects against resistant strains of P. yoelii in Swiss albino mice. The findings justify the use of the extract of P. amarus in traditional medicine practice, for the treatment of malaria infections.

Hypocholesterolemic activity from the leaf extracts of Cnidoscolus chayamansa

The aim of this study was to determine the hypocholesterolemic activity of Cnidoscolus chayamansa. In an in vivo model, high-cholesterol diet administered to mice Balb/c induced hypercholesterolemia. Three extracts from Cnidoscolus chayamansa (ethanol, methanol and an aqueous extract) were tested on hypercholesterolemic mice. Active extracts were assessed against the in vitro inhibitory activity of the same three extracts on the HMG-CoA reductase enzyme by using Vero cells. The specific chemical groups present in the phytochemical extracts were also determined. Only the aqueous extract (at either doses employed) showed a significant cholesterol reduction (27.9 and 31.1%, for 50 and 100 mg kg(-1), respectively P<0.01). The extract did not inhibit the HMG-CoA reductase enzyme, suggesting that its compounds act at another level in cholesterol metabolism. Reactions to secondary metabolites indicate the presence of alkaloids in the aqueous and ethanol extracts and phenol hydroxyls in the ethanol and methanol extracts.

Further evaluation of antihyperglycaemic activity of Hunteria umbellata (K. Schum) Hallier f. seed extract in experimental diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

In African traditional medicine, water decoction made from the dry seeds of Hunteria umbellata (K. Schum) Hallier f. is highly valued in the management of diabetes mellitus.

AIM

In the present study, the antihyperglycaemic activity of the seed aqueous extract of Hunteria umbellate (K. Schum) Hallier f. (HU) was investigated in alloxan-induced, high fructose- and dexamethasone-induced hyperglycaemic rats.

MATERIALS AND METHODS

Alloxan-induced, dexamethasone-induced and high fructose-induced hyperglycaemic rats were treated with single, daily oral administration of 1 mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg and 200 mg/kg of HU in Groups III, IV, V and VI, for 14 days, 21 days and 8 weeks, respectively. The effects of these drugs on FBG, free plasma insulin levels, HbA(1c), serum TG and TC, and insulin resistance indices were investigated.

RESULTS

Data generated in the current study showed that glibenclamide and graded oral doses of HU caused significant dose related (p < 0.05, < 0.01 and < 0.001) reductions in FBG when compared to the values obtained for the model control (Group II) rats. Similarly, daily oral administration of 66.7 g/kg fructose to rats for 8 weeks was associated with significant (p < 0.001) hyperglycaemia, elevations in plasma HbA(1c), free insulin, fasting insulin resistance indices, serum TG, and cholesterol. However, concomitant oral treatments with 1mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg, and 200 mg/kg of HU extract significantly and dose dependently (p < 0.05, < 0.01 and < 0.001) attenuated development of hyperglycaemia, decreased levels of plasma HbA(1c), free insulin, and serum triglyceride and cholesterol, in the Groups III, IV, V and VI rats, respectively, when compared to fructose-induced hyperglycaemic (Group II) rats. Similar effect was also recorded in the dexamethasone-induced hyperglycaemic rats.

CONCLUSION

Results of this study suggest that the hypoglycaemic and antihyperlipidaemic effects of HU are mediated via enhanced peripheral glucose uptake and improvements in hyperinsulinaemia.

Radioprotective properties of polyphenols from Phyllanthus amarus Linn

Radioprotective activity of pure compounds isolated from the plant Phyllanthus amarus was studied using rat liver mitochondria and pBR322 plasmid DNA as an in vitro model system. These compounds were ellagitannins namely amariin, 1-galloyl-2,3-dehydrohexahydroxydiphenyl (DHHDP)-glucose, repandusinic acid, geraniin, corilagin, phyllanthusiin D, and flavonoids namely rutin, and quercetin 3-O-glucoside. The activity was then correlated with their hydroxyl and superoxide radical scavenging activity. Both ellagitannins and flavonoids effectively prevented lipid peroxidation and protein oxidation in mitochondria. The compounds also prevented radiation induced single strand breaks in pBR322 plasmid DNA. The radioprotective activity of ellagitannins and flavonoids could be due to their ability to scavenge different radicals more or less efficiently, relieving the oxidative stress. Protection conferred by flavonoids, rutin and quercetin 3-O-glucoside to rat liver mitochondria and plasmid pBR322 DNA from radiation induced damage was due to their strong hydroxyl radical scavenging activity. The inhibitory effect of ellagitannins on lipid peroxidation in liver mitochondria was due to their efficient superoxide radical scavenging ability. This is the first report about the radioprotective activity of pure ellagitannins from Phyllanthus amarus.

Two new lignans from Phyllanthus amarus

Two new lignans, 3-(3,4-dimethoxy-benzyl)-4-(7-methoxy-benzo[1,3]dioxol-5-yl-methyl)-dihydrofuran-2-one (1) and 4-(3,4-dimethoxy-phenyl)-1-(7-methoxy-benzo[1,3]dioxol-5-yl)-2,3-bis-methoxymethyl-butan-1-ol (2), were isolated from the leaves of Phyllanthus amarus and their structures were established by spectral analysis. Additionally, eight known lignans were also isolated and characterized.

Protective effect of the aqueous leaf and seed extract of Phyllanthus amarus on gentamicin and acetaminophen-induced nephrotoxic rats

AIM OF THE STUDY

In African traditional medicine, different parts of Phyllanthus amarus Schum. and Thonn. (family: Euphorbiaceae) are highly valued for the treatment of array of human diseases including hepatic and urolithic and/or other renal diseases. In the present study, single oral 100-400mg/kg/day of the leaf and seed aqueous extract of Phyllanthus amarus (PA) were studied for their protective effects in acetaminophen- and gentamicin-induced nephrotoxic Wistar rats for 14 days.

MATERIALS AND METHODS

In each model of nephrotoxicities, thirty adult male Wistar rats were evenly divided into 5 groups. Groups I and II served as untreated and model controls, respectively while groups III-V were the treatment groups which were pretreated with 100-400mg/kg/day of PA 1hr before each dose of the nephrotoxicants for 14 days. On the 15th day, blood samples for serum urea and creatinine while the rat kidneys for histology were obtained under inhaled diethyl ether anesthesia.

RESULTS

In the acetaminophen nephrotoxic rats, 100-400mg/kg/day significantly (p<0.05, p<0.01, p<0.001) attenuated elevations in the serum creatinine and blood urea nitrogen levels in dose related fashion, as well as, attenuation of acetaminophen-induced tubulonephrosis. Similar effects were also recorded in the gentamicin model of acute renal injury. Results suggest that the nephroprotective effect of PA could be due to the inherent antioxidant and free-radical-scavanging principle(s) contained in the extract.

CONCLUSIONS

In the near future, PA could constitute a lead to discovery of a novel drug for the treatment of drug-induced nephrotoxicity.