In vitro antiplasmodial activity of callus culture extracts and fractions from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae): part 2

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.

Bioactive Compounds from Medicinal Plants in Myanmar

Myanmar is a country with rich natural resources and of these, medicinal plants play a vital role in the primary health care of its population. The people of Myanmar have used their own system of traditional medicine inclusive of the use of medicinal plants for 2000 years. However, systematic and scientific studies have only recently begun to be reported. Researchers from Japan, Germany, and Korea have collaborated with researchers in Myanmar on medicinal plants since 2000. During the past two decades, over 50 publications have been published in peer-reviewed journals. Altogether, 433 phytoconstituents, including 147 new and 286 known compounds from 26 plant species consisting of 29 samples native to Myanmar, have been collated. In this contribution, phytochemical and biological investigations of these plants, including information on traditional knowledge are compiled and discussed.

Antimalarial herbal remedies of Bukavu and Uvira areas in DR Congo: An ethnobotanical survey

ETHNOPHARMACOLOGICAL RELEVANCE

The main objective of the present study was to collect and gather information on herbal remedies traditionally used for the treatment of malaria in Bukavu and Uvira, two towns of the South Kivu province in DRC.

MATERIAL AND METHODS

Direct interview with field enquiries allowed collecting ethnobotanical data; for each plant, a specimen was harvested in the presence of the interviewed traditional healers (THs). The recorded information included vernacular names, morphological parts of plants, methods of preparation and administration of remedies, dosage and treatment duration. Plants were identified with the help of botanists in the herbaria of INERA/KIPOPO (DRC) and the Botanic Garden of Meise (Belgium), where voucher specimens have been deposited. The results were analysed and discussed in the context of previous published data.

RESULTS

Interviewees cited 45 plant species belonging to 41 genera and 21 families used for the treatment of malaria. These plants are used in the preparation of 52 recipes, including 25 multi-herbal recipes and 27 mono-herbal recipes. Apart of Artemisia annua L. (Asteraceae; % Citation frequency = 34%) and Carica papaya L. (Caricaceae; % Citation frequency = 34%), the study has highlighted that the most represented families are Asteraceae with 12 species (26%), followed by Fabaceae with 7 species (16%) and Rubiaceae with 4 species (9%). For a majority of plants, herbal medicines are prepared from the leaves in the form of decoction and administered by oral route.

CONCLUSION

Literature data indicate that part of cited species are already known (38%) and/or studied (30%) for antimalarial properties, which gives credit to the experience of Bukavu and Uvira interviewees and some level of confidence on collected information. The highly cited plants should be investigated in details for the isolation and identification of active ingredients, a contribution to the discovery of new possibly effective antimalarials.

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.

Antimalarial activity of medicinal plants from the Democratic Republic of Congo: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is the most prevalent parasitic disease and the foremost cause of morbidity and mortality in the Democratic Republic of Congo. For the management of this disease, a large Congolese population recourses to traditional medicinal plants. To date the efficacy and safety of many of these plants have been validated scientifically in rodent malaria models. In order to generate scientific evidence of traditional remedies used in the Democratic Republic of Congo for the management of malaria, and show the potential of Congolese plants as a major source of antimalarial drugs, this review highlights the antiplasmodial and toxicological properties of the Congolese antimalarial plants investigated during the period of 1999-2014. In doing so, a useful resource for further complementary investigations is presented. Furthermore, this review may pave the way for the research and development of several available and affordable antimalarial phytomedicines.

MATERIALS AND METHODS

In order to get information on the different studies, a Google Scholar and PubMed literature search was performed using keywords (malaria, Congolese, medicinal plants, antiplasmodial/antimalarial activity, and toxicity). Data from non-indexed journals, Master and Doctoral dissertations were also collected.

RESULTS

Approximately 120 extracts and fractions obtained from Congolese medicinal plants showed pronounced or good antiplasmodial activity. A number of compounds with interesting antiplasmodial properties were also isolated and identified. Some of these compounds constituted new scaffolds for the synthesis of promising antimalarial drugs. Interestingly, most of these extracts and compounds possessed high selective activity against Plasmodium parasites compared to mammalian cells. The efficacy and safety of several plant-derived products was confirmed in mice, and a good correlation was observed between in vitro and in vivo antimalarial activity. The formulation of several plant-derived products also led to some clinical trials and license of three plant-derived drugs (Manalaria(®), Nsansiphos(®), and Quinine Pharmakina(®)).

CONCLUSION

The obtained results partly justify and support the use of various medicinal plants to treat malaria in folk medicine in the Democratic Republic of Congo. Antimalarial plants used in Congolese traditional medicine represent an important source for the discovery and development of new antimalarial agents. However, in order to ensure the integration of a larger number of plant-derived products in the Congolese healthcare system, some parameters and trends should be considered in further researches, in agreement with the objectives of the "Traditional Medicine Strategy" proposed by the World Health Organization in 2013. These include evaluation of geographical and seasonal variation, investigation of reproductive biology, assessment of prophylactic antimalarial activity, evaluation of natural products as adjuvant antioxidant therapy for malaria, development of plant-based combination therapies and monitoring of herbal medicines in pharmacovigilance systems.

In vitro and in vivo anti-hepatitis B virus activities of the lignan nirtetralin B isolated from Phyllanthus niruri L

ETHNOPHARMACOLOGICAL RELEVANCE

Nirtetralin B, a new lignan first reported by our team, is isolated from Phyllanthus niruri L. This plant has long been used in folk medicine for liver protection and antihepatitis B in many Asian countries. This study was designed to evaluate the anti-hepatitis B virus activity of nirtetralin B using HepG2.2.15 cells and duck hepatitis B virus (DHBV) infected ducks as in vitro and in vivo models.

MATERIALS AND METHODS

Nirtetralin B was isolated from Phyllanthus niruri L. (Euphorbiaceae) by extraction and chromatographic procedures and the anti-hepatitis B virus activity was evaluated both in vitro and in vivo. The human HBV-transfected liver cell line HepG2.2.15 was used in vitro assay. And the in vivo anti-hepatitis B virus activity was evaluated on the expression of HBV replication, HBsAg, HBeAg, ALT and AST on day 0, 7, 14, 17 after nirtetralin B was dosed intragastricly (i.g.) once a day for 14 days at the dosages of 25, 50 and 100mg/kg/day in the duck hepatitis B virus (DHBV) infected ducks.

RESULTS

In the human HBV-transfected liver cell line HepG2.2.15, nirtetralin B effectively suppressed the secretion of the HBV antigens in a dose-dependent manner with IC50 values for HBsAg of 17.4μM, IC50 values for HBeAg of 63.9μM. In DHBV-infected ducklings, nirtetralin B significantly reduced the serum DHBV DNA, HBsAg, HBeAg, ALT and AST. And analysis of the liver pathological changes confirmed the hepatoprotective effect of nirtetralin B.

CONCLUSION

The experimental data demonstrated that nirtetralin B exhibits anti-hepatitis B virus activity both in vitro and in vivo.

Male rat hormone imbalance, testicular changes and toxicity associated with aqueous leaf extract of an antimalarial plant: Phyllanthus niruri

CONTEXT

Phyllanthus niruri L. (Euphorbiaceae), a medicinal plant traditionally known for dissolving kidney stones, is used prophylactically as an antimalarial agent.

OBJECTIVE

The study was undertaken to determine its effect on some male hormones and other toxicological properties due to paucity of its data despite its wide use.

MATERIAL AND METHODS

Male Sprague-Dawley rats (100-140 g) were used. Group 1 [control group (C), n = 6] received water. Group 2 [low-dose test group (LD), n = 6] received 50 mg/kg body weight (b.wt.) aqueous leaf extract orally. Group 3 [high-dose test group (HD), n = 6] received 500 mg/kg b.wt. extract for 90 days. Upon sacrifice, among other organs the testes were harvested. Blood samples drawn were used for biochemical (including progesterone, estrogen and testosterone), cytotoxicity and hematological assays.

RESULTS

C, LD and HD estrogen values were 192 ± 25, 385 ± 122 and 962 ± 357 pg/ml, respectively. In the same order, progesterone values were 96 ± 24, 155 ± 45 and 320 ± 80 pg/ml, respectively. Testosterone levels were 5210 ± 1090, 4710 ± 220 and 4500 ± 580 pg/ml, respectively. Significant differences were observed in the estrogen and progesterone levels (p = 0.001). Degenerative changes were observed histologically. Cytotoxicity at 50% (CC50) was 10.0 µg/ml.

DISCUSSION AND CONCLUSION

This antimalarial plant is mildly cytotoxic with male antifertility properties.

Anti-hyperalgesic activity of corilagin, a tannin isolated from Phyllanthus niruri L. (Euphorbiaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Corilagin (β-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-D-glucose) is a tannin isolated from Phyllanthus niruri (Euphorbiaceae). This plant is well known for their therapeutic purposes to treat several diseases associated with dolorous process and are used in several ethno-medicines in tropical and subtropical countries.

AIM OF THE STUDY

This study was designed to evaluate the anti-hyperalgesic activity of corilagin using chemically and thermally based nociception models in mice.

MATERIALS AND METHODS

Corilagin was isolated from Phyllanthus niruri (Euphorbiaceae) by extraction and chromatographic procedures and the anti-hyperalgesic activity was evaluated by using writhing, formalin, capsaicin, glutamate and hot plate tests in mice.

RESULTS

Corilagin presented activity in acetic acid model with the ID50 calculated value of 6.46 (3.09-13.51) being about 20.6 fold more potent than acetylsalicylic acid. It also exhibited activity against the first phase of formalin test with ID50 value of 18.38 (15.15-22.59) μmol/kg. In the capsaicin and glutamate models, corilagin demonstrated significant activity at the 3 mg/kg.

CONCLUSION

The experimental data demonstrated that corilagin exhibits anti-hyperalgesic activity that may be due to interaction with the glutamatergic system.

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.

The quantification of ellagic acid in the crude extract of Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae)

INTRODUCTION

Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae), already well known for its antiviral, antihyperglycaemic and antihepatotoxic effects, is also investigated for its antimalarial activity. The major constituent of the crude extract of the whole plant was isolated and identified in this research to be ellagic acid, for which antiplasmodial activity already has been reported.

OBJECTIVE

Because of the potential of the plant and the interesting properties of ellagic acid, an analytical method can be useful for the standardisation of the extracts to allow further biological and pharmacological investigations. In order to obtain an easily performable and inexpensive method, an HPLC analysis was developed and validated.

METHODOLOGY

The samples were dissolved in DMSO, ultrasonicated for 15 min, and diluted with 50% methanol. Analysis was performed using water and methanol containing 0.06% TFA and the peaks were detected at 254 nm.

RESULTS

Ellagic acid showed a linear relationship in the range of 1.74-20.91 µg/mL and a single-point calibration was allowed. The method was shown to be precise with respect to time (RSD of 1.84%, 3 days, n = 6) and concentration (RSD of 2.54%, 3 levels, n = 6). The overall mean content of ellagic acid was 2.06%. A recovery experiment was performed and it showed an accuracy of 100.4%.

CONCLUSION

Based on the obtained results, it can be concluded that the newly developed method is suitable for its purpose, namely the determination of ellagic acid in the crude extract of P. amarus.

Analysis of additivity and synergism in the anti-plasmodial effect of purified compounds from plant extracts

In the search for antimalarials from ethnobotanical origin, plant extracts are chemically fractionated and biological tests guide the isolation of pure active compounds. To establish the responsibility of isolated active compound(s) to the whole antiplasmodial activity of a crude extract, the literature in this field was scanned and results were analysed quantitatively to find the contribution of the pure compound to the activity of the whole extract. It was found that, generally, the activity of isolated molecules could not account on their own for the activity of the crude extract. It is suggested that future research should take into account the “drugs beside the drug”, looking for those products (otherwise discarded along the fractionation process) able to boost the activity of isolated active compounds.

Antiplasmodial activity of botanical extracts against Plasmodium falciparum

The absence of a vaccine and the rampant resistance to almost all antimalarial drugs have accentuated the urgent need for new antimalarial drugs and drug targets for both prophylaxis and chemotherapy. The aim of the study was to discover effective plant extracts against Plasmodium falciparum. In the present study, the hexane, chloroform, ethyl acetate, acetone, and methanol extracts of Citrus sinensis (peel), Leucas aspera, Ocimum sanctum, Phyllanthus acidus (leaf), Terminalia chebula (seed) were tested for their antimalarial activity against chloroquine (CQ)-sensitive (3D7) strain of P. falciparum which was cultured following the candle-jar method. Antimalarial evaluations of daily replacement of culture medium containing CQ and different plant crude extracts were performed on 96-well plates at 37°C for 24 and 48 h. Parasitemia was determined microscopically on thin-film Giemsa-stained preparations. Plant extracts were tested for their cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on human laryngeal cancer cell line (HEp-2) and normal cell line (Vero). Out of the 25 extracts tested, six showed good (IC(50) 4.76-22.76 μg/mL), 15 exhibited moderate (IC(50) 31.42-88.03 μg/mL), while four displayed mild (IC(50) > 100 μg/mL) antiplasmodial activity. The leaf ethyl acetate and methanol extracts of L. aspera; ethyl acetate, acetone, and methanol extracts of P. acidus; and seed acetone extract of T. chebula had good antiplasmodial activity (IC(50) = 7.81, 22.76, 9.37, 14.65, 12.68, and 4.76 μg/mL) with selectivity indices 5.43, 2.04, 4.88, 3.35, 3.42, and 9.97 for HEp-2 and >5.79, >2.20, >11.75, >3.41, >3.94, and >7.38 for Vero cells, respectively. These analyses have revealed for the first time that the components present in the solvent extracts of L. aspera, P. acidus, and T. chebula have antiplasmodial activity. The high antiplasmodial activity observed make these plants good candidates for isolation of anti-protozoal compounds which could serve as new lead structures for drug development.

Phytochemicals from Phyllanthus niruri Linn. and their pharmacological properties: a review

This review discusses the medicinal plant Phyllanthus niruri Linn. (Euphorbiaceae), its wide variety of phytochemicals and their pharmacological properties. The active phytochemicals, flavonoids, alkaloids, terpenoids, lignans, polyphenols, tannins, coumarins and saponins, have been identified from various parts of P. niruri. Extracts of this herb have been proven to have therapeutic effects in many clinical studies. Some of the most intriguing therapeutic properties include anti-hepatotoxic, anti-lithic, anti-hypertensive, anti-HIV and anti-hepatitis B. Therefore, studies relating to chemical characteristics and structural properties of the bioactive phytochemicals found in P. niruri are very useful for further research on this plant as many of the phytochemicals have shown preclinical therapeutic efficacies for a wide range of human diseases, including HIV/AIDS and hepatitis B.