In vitro antiviral activity of peptide-rich extracts from seven Nigerian plants against three non-polio enterovirus species C serotypes.

BACKGROUND: As frequent viral outbreaks continue to pose threat to public health, the unavailability of antiviral drugs and challenges associated with vaccine development underscore the need for antiviral drugs discovery in emergent moments (endemic or pandemic). Plants in response to microbial and pest attacks are able to produce defence molecules such as antimicrobial peptides as components of their innate immunity, which can be explored for viral therapeutics. METHODS: In this study, partially purified peptide-rich fraction (P-PPf) were obtained from aqueous extracts of seven plants by reverse-phase solid-phase extraction and cysteine-rich peptides detected by a modified TLC method. The peptide-enriched fractions and the aqueous (crude polar) were screened for antiviral effect against three non-polio enterovirus species C members using cytopathic effect reduction assay. RESULTS: In this study, peptide fraction obtained from Euphorbia hirta leaf showed most potent antiviral effect against Coxsackievirus A13, Coxsackievirus A20, and Enterovirus C99 (EV-C99) with IC50 < 2.0 µg/mL and selective index ≥ 81. EV-C99 was susceptible to all partially purified peptide fractions except Allamanda blanchetii leaf. CONCLUSION: These findings establish the antiviral potentials of plants antimicrobial peptides and provides evidence for the anti-infective use of E. hirta in ethnomedicine. This study provides basis for further scientific investigation geared towards the isolation, characterization and mechanistic pharmacological study of the detected cysteine-rich peptides.

In vitro antiviral activity of twenty-seven medicinal plant extracts from Southwest Nigeria against three serotypes of echoviruses.

BACKGROUND: Echoviruses, a serotype of enteroviruses, infect millions of people globally and there is no specific drug treatment or vaccine available for its management. The screening of medicinal plants used locally for the treatment of infectious diseases, can provide a reliable option in the discovery of potent therapeutic compounds. This study was carried out to investigate the antiviral activities of 27 medicinal plant extracts, belonging to 26 different plant species, selected from Nigerian ethnobotany, against echovirus 7, 13 and 19 serotypes (E7, E13 and E19, respectively). METHODS: The plants were macerated in methanol and the cytotoxicities of the crude extracts were evaluated on the rhabdomyosarcoma cell line using the MTT assay. The antiviral activity of the plant extracts and fractions against echoviruses (E7, E13, and E19) was determined using the neutralisation assay, an assay that measures the inhibition of cytopathic effect on cell culture. RESULTS: The crude extract of Macaranga barteri leaves had the highest cytotoxicity with CC50 value of 0.27 µg/mL. This was followed by Crinum jagus (9.88 µg/mL) and Terminalia ivorensis (12.14 µg/mL). The antiviral screening showed that ten out of the 27 crude plant extracts tested were active on E7 and E19, inhibiting the cytopathic effect of the virus in tissue culture. None of the extracts inhibited the cytopathic effect caused by E13 serotype. Amongst the active plant extracts, the methanol extract of M. barteri leaves had the highest antiviral activity on both E7 and E9 with IC50 values of 0.028 and 0.0017 ng/mL, respectively, followed by the Ageratum conyzoides extract (0.208 µg/mL, E7; 0.006 µg/mL, E19) and Mondia whitei extract (0.038 µg/mL, E7; 0.005 µg/mL, E19). Amongst the fractions of M. barteri, the DCM fraction was most the active and selective on E7 (IC50 = 0.0075 ng/mL; SI = 19,896.54) and E19 (IC50 = 0.0175 ng/mL; SI = 8581.24). CONCLUSION: Our research has demonstrated that Macaranga barteri extracts has potent antiviral activity against echoviruses E7 and E19, and our findings suggest that this extract may have potential as a therapeutic agent in the treatment of enteroviral infections.

In vitro cytotoxic activity of medicinal plants from Nigeria ethnomedicine on Rhabdomyosarcoma cancer cell line and HPLC analysis of active extracts.

BACKGROUND: Cancer is a leading cause of death world-wide, with approximately 17.5 million new cases and 8.7 million cancer related deaths in 2015. The problems of poor selectivity and severe side effects of the available anticancer drugs, have demanded the need for the development of safer and more effective chemotherapeutic agents. The present study was aimed at determining the cytotoxicities of 31 medicinal plants extracts, used in Nigerian ethnomedicine for the treatment of cancer. METHODS: The plant extracts were screened for cytotoxicity, using the brine shrimp lethality assay (BSLA) and MTT cytotoxicity assay. Rhabdomyosarcoma (RD) cell line, normal Vero cell line and the normal prostate (PNT2) cell line were used for the MTT assay, while Artemia salina nauplii was used for the BSLA. The phytochemical composition of the active plant extracts was determined by high performance liquid chromatography (HPLC) analysis. RESULTS: The extract of Eluesine indica (L.) Gaertn (Poaceae), with a LC50 value of 76.3 µg/mL, had the highest cytotoxicity on the brine shrimp larvae compared to cyclophosphamide (LC50 = 101.3 µg/mL). Two plants extracts, Macaranga barteri Mull. Arg. (Euphorbiaceae) and Calliandra portoricensis (Jacq.) Benth (Leguminosae) exhibited significant cytotoxic activity against the RD cell line and had comparable lethal activity on the brine shrimps. Further cytotoxic investigation showed that the dichloromethane fraction of Macaranga barteri (DMB) and the ethyl acetate fraction of Calliandra portoricensis (ECP), exhibited approximately 6-fold and 4-fold activity, respectively, compared to cyclophosphamide on RD cell line. Determination of selective index (SI) using Vero and PNT2 cell line indicated that DMB and ECP displayed a high degree of selectivity against the cancer cell under investigation. HPLC analysis showed that 3,5dicaffeoylquinic acid, acteoside, kampferol-7-O-glucoside and bastadin 11 were the major components of DMB while the major components of ECP were neurolenin B, nigrosporolide and trans-geranic acid. CONCLUSION: The results demonstrate the cytotoxicity of Macaranga barteri and Calliandra portoricensis extracts, which are used in Nigerian folklore for cancer treatment.

Environmental surveillance for polioviruses in the Global Polio Eradication Initiative.

This article summarizes the status of environmental surveillance (ES) used by the Global Polio Eradication Initiative, provides the rationale for ES, gives examples of ES methods and findings, and summarizes how these data are used to achieve poliovirus eradication. ES complements clinical acute flaccid paralysis (AFP) surveillance for possible polio cases. ES detects poliovirus circulation in environmental sewage and is used to monitor transmission in communities. If detected, the genetic sequences of polioviruses isolated from ES are compared with those of isolates from clinical cases to evaluate the relationships among viruses. To evaluate poliovirus transmission, ES programs must be developed in a manner that is sensitive, with sufficiently frequent sampling, appropriate isolation methods, and specifically targeted sampling sites in locations at highest risk for poliovirus transmission. After poliovirus ceased to be detected in human cases, ES documented the absence of endemic WPV transmission and detected imported WPV. ES provides valuable information, particularly in high-density populations where AFP surveillance is of poor quality, persistent virus circulation is suspected, or frequent virus reintroduction is perceived. Given the benefits of ES, GPEI plans to continue and expand ES as part of its strategic plan and as a supplement to AFP surveillance.

In vitro anti-enteroviral activity of stilbenoids isolated from the leaves of Macaranga barteri.

The anti-enteroviral activity of three stilbenoids isolated from the leaves of Macaranga barteri was investigated using the cytopathic effect reduction assay. The stilbenes were inactive against echovirus E13 but showed activity against echoviruses E7 and E19. In particular, vedelianin (2), schweinfurthin G (3) and mappain (1) elicited antiviral activity on E19 with IC50 values of 0.0036 nM, 0.018 nM and 0.24 µM, respectively. Vedelianin (2) showed the best selectivity profile amongst the isolated compounds with selectivity index values of 31 and 216 against E7 and E19, respectively. It is possible these compounds may be responsible for the traditional use of Macaranga barteri in the treatment of viral infections.

Phytochemicals from Kigelia pinnata leaves show antioxidant and anticancer potential on human cancer cell line.

Studies suggest that the traditional applications of Kigelia pinnata leaves have beneficial effects against oxidative stress-mediated diseases and cancers. The pulverized dried leaves of K. pinnata were extracted with hexane, ethyl acetate, and methanol sequentially, and the crude extracts were fractionated by silica gel column chromatography with solvent gradient of increasing polarity. 3-hydro-4,8-phytene, trans-phytol, (9Z,12Z)-methyl octadeca-9,12-dienoate, and two oil fractions were obtained. The chemical compositions of chromatographic fractions were determined using gas chromatography-mass spectroscopy. The structure elucidations of the isolated compounds were based on FTIR, MS, and NMR spectral data analyses. These along with the crude extracts were examined for their antioxidant activities using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and 2,2-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) assays. Total phenolic contents were also determined. The crude extracts and purified compounds were evaluated on the rhabdomyosarcoma human cancer cell for their cytotoxicity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays. The methanol extract was richer in phenolics and was most potent as antioxidant and cytotoxic agent among all the substances tested. Among the fractions and pure compounds, the two oil fractions showed more cytotoxicity potency, with IC50s of 143.4±0.5 and 147.9±1.3 ng/mL, which is more significant than the reference standard, cyclophosphamide (165.6±1.0 ng/mL). 3-hydro-4,8-phytene showed lower antioxidant and cytotoxicity potential (IC50=1818±5.2 µg/mL and 171.7±0.8 ng/mL, respectively). Trans-phytol did not show a high cytotoxic power (IC50=769.8±4.3 ng/mL). The comparatively high cytotoxicity index of (9Z, 12Z)-methyl octadeca-9,12-dienoate (IC50=153.3±0.1 ng/mL) indicated that it may be one of the principal cytotoxic agent in the ethyl acetate extract. These results suggest that the leaves of K. pinnata possess tumor cytotoxic potential and could be part of a drug combination for future cancer chemotherapy.