Areca catechu-From farm to food and biomedical applications.

The family Arecaceae includes 181 genera and 2,600 species with a high diversity in physical characteristics. Areca plants, commonly palms, which are able to grow in nearly every type of habitat, prefer tropical and subtropical climates. The most studied species Areca catechu L. contains phytochemicals as phenolics and alkaloids with biological properties. The phenolics are mainly distributed in roots followed by fresh unripe fruits, leaves, spikes, and veins, while the contents of alkaloids are in the order of roots, fresh unripe fruits, spikes, leaves, and veins. This species has been reputed to provide health effects on the cardiovascular, respiratory, nervous, metabolic, gastrointestinal, and reproductive systems. However, in many developing countries, quid from this species has been associated with side effects, which include the destruction of the teeth, impairment of oral hygiene, bronchial asthma, or oral cancer. Despite these side effects, which are also mentioned in this work, the present review collects the main results of biological properties of the phytochemicals in A. catechu. This study emphasizes the in vitro and in vivo antioxidant, antimicrobial, anticancer, and clinical effectiveness in humans. In this sense, A. catechu have demonstrated effectiveness in several reports through in vitro and in vivo experiments on disorders such as antimicrobial, antioxidant, or anticancer. Moreover, our findings demonstrate that this species presents clinical effectiveness on neurological disorders. Hence, A. catechu extracts could be used as a bioactive ingredient for functional food, nutraceuticals, or cosmeceuticals. However, further studies, especially extensive and comprehensive clinical trials, are recommended for the use of Areca in the treatment of diseases.

Bulbine frutescens phytochemical inhibits notch signaling pathway and induces apoptosis in triple negative and luminal breast cancer cells.

Breast cancer (BCa) is the most commonly diagnosed lethal cancer in women worldwide. Notch signaling pathway is directly linked to BCa recurrence and aggressiveness. Natural remedies are becoming a prime choice to overcome against cancer due to lesser side effect and cost-effectiveness. Bulbine frutescens (Asphodelaceae), a traditional medicinal plant in South Africa possess bioactive flavonoids and terpenoids. Polar (methanol) and non-polar (hexane) B. frutescens plant extracts were prepared. GC-MS analysis revealed the differential presence of secondary metabolites in both methanolic and hexane extracts. We hereby first time evaluated the anticancer potential of B. frutescens methanolic and hexane extract in triple-negative and luminal BCa cells. B. frutescens extracts significantly decreased cell viability (IC50 4.8-28.4 µg/ml) and induced cell cycle arrest at G1 phase in MDA-MB-231 and T47D cells as confirmed by spectrophotometry and flow cytometry technique. RT-PCR analysis of cell cycle (cyclin D1, CDK4, and p21) and apoptosis modulating genes (caspase 3, Bcl2 and survivin) revealed upexpression of p21, and caspase 3, and down expression of cyclin D1, CDK4, Bcl2 and survivin genes in extract-treated BCa cells. Fluorescence spectrophotometry and confocal microscopy showed B. frutescens induced nuclear morphology and mitochondrial integrity disruption, and increased reactive oxygen species production in MDA-MB-231 and T47D cells. Flow cytometric apoptosis analysis of B. frutescens extracts treated MDA-MB-231 cells showed ≈13% increase in early apoptotic population in comparison to non-treated cells. Dual-Luciferase Reporter assay confirmed notch promoter inhibitory activity of B. frutescens extracts. Moreover, RTPCR analysis showed down regulation of notch responsive genes (Hes1 and Hey1) at transcription levels in extract-treated BCa cells. Western Blot analysis showed increased procaspase 3 protein expression in extract-treated BCa cells. In all the assays methanolic extract showed better anti-cancer properties. Literature-based identification of methanol soluble phytochemicals in B. frutescens and in silico docking study revealed Bulbineloneside D as a potent ϒ-secretase enzyme inhibitor. In comparison to standard notch inhibitor, lead phytochemical showed two additional hydrophobic interactions with Ala80 and Leu81 amino acids. In conclusion, B. frutescens phytochemicals have cell cycle arrest, ROS production, apoptosis induction, and mitochondria membrane potential disruption efficacy in breast cancer cells. B. frutescens phytochemicals have the ability to downregulate the notch signaling pathway in triple-negative and luminal breast cancer cells.

Anti-HIV Activity of Ocimum labiatum Extract and Isolated Pheophytin-a.

Ocimum plants are traditionally used to manage HIV/AIDS in various African countries. The effects of Ocimum labiatum extract on HIV-1 protease (PR) and reverse transcriptase (RT) is presented here along with characterization of an identified bioactive compound, achieved through ¹H- and 13C-NMR. The extract's effect on HIV-1 replication was assessed by HIV-1 p24 antigen capture. Cytotoxicity of samples was evaluated using tetrazolium dyes and real-time cell electronic sensing (RT-CES). Ocimum labiatum inhibited HIV-1 PR with an IC50 value of 49.8 ± 0.4 µg/mL and presented weak inhibition (21%) against HIV-1 RT. The extract also reduced HIV-1 replication in U1 cells at a non-cytotoxic concentration (25 µg/mL). The CC50 value of the extract in U1 cells was 42.0 ± 0.13 µg/mL. The HIV-1 PR inhibiting fraction was purified using prep-HPLC and yielded a chlorophyll derivative, pheophytin-a (phy-a). Phy-a inhibited HIV-1 PR with an IC50 value of 44.4 ± 1.5 µg/mL (51 ± 1.7 µM). The low cytotoxicity of phy-a in TZM-bl cells was detected by RT-CES and the CC50 value in U1 cells was 51.3 ± 1.0 µg/mL (58.9 ± 1.2 µM). This study provides the first in vitro evidence of anti-HIV activity of O. labiatum and isolated phy-a, supporting further investigation of O. labiatum for lead compounds against HIV-1.

Triterpenoids from Ocimum labiatum Activates Latent HIV-1 Expression In Vitro: Potential for Use in Adjuvant Therapy.

Latent HIV reservoirs in infected individuals prevent current treatment from eradicating infection. Treatment strategies against latency involve adjuvants for viral reactivation which exposes viral particles to antiretroviral drugs. In this study, the effect of novel triterpenoids isolated from Ocimum labiatum on HIV-1 expression was measured through HIV-1 p24 antigen capture in the U1 latency model of HIV-1 infection and in peripheral blood mononuclear cells (PBMCs) of infected patients on combination antiretroviral therapy (cART). The mechanism of viral reactivation was determined through the compound's effect on cytokine production, histone deacetylase (HDAC) inhibition, and protein kinase C (PKC) activation. Cytotoxicity of the triterpenoids was determined using a tetrazolium dye and flow cytometry. The isolated triterpene isomers, 3-hydroxy-4,6a,6b,11,12,14b-hexamethyl-1,2,3,4,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-octadecahydropicene-4,8a-dicarboxylic acid (HHODC), significantly (p < 0.05) induced HIV-1 expression in a dose-dependent manner in U1 cells at non-cytotoxic concentrations. HHODC also induced viral expression in PBMCs of HIV-1 infected patients on cART. In addition, the compound up-regulated the production of interleukin (IL)-2, IL-6, tumour necrosis factor (TNF)-α, and interferon (IFN)-γ but had no effect on HDAC and PKC activity, suggesting cytokine upregulation as being involved in latency activation. The observed in vitro reactivation of HIV-1 introduces the adjuvant potential of HHODC for the first time here.

Antioxidant activity of a halogenated monoterpene isolated from a Namibian marine algal Plocamium species.

The antioxidant potential of various marine natural products is well documented. The aim of this study was to evaluate the antioxidant potential of a rare halogenated monoterpene, namely; 1E,3R,4S,5E,7Z-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (1) for the first time. This compound was isolated from a Namibian red algal Plocamium species. The antioxidant activity of the compound was evaluated using a series of antioxidant assays, namely; 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH), reducing power, nitric oxide (NO) and hydrogen peroxide (H2O2). The compound demonstrated remarkable DPPH, NO and H2O2 scavenging activities with IC50 values of 0.05 ± 0.01, 4.18 ± 0.22 and 5.58 ± 1.11 mM, respectively. The reducing power of the compound increased with an increase in concentration. These results were compared to the absorbance of ascorbic acid, which was used as a standard control in all the antioxidant assays. The results strongly suggest that compound 1 is a promising antioxidant agent with potential commercial applications.

In vitro anti-HIV and antioxidant activity of Hoodia gordonii (Apocynaceae), a commercial plant product.

BACKGROUND: Hoodia gordonii products are widely commercialized for anti-obesity purposes; however, minimal research is available on the other health properties demonstrated by this popular herbal plant. METHODS: H. gordonii crude extracts (ethanol and ethyl acetate) were assayed for in vitro anti-HIV-1 protease (PR), reverse transcriptase (RT) and integrase activity. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power assays were used for the antioxidant analysis. In addition, qualitative and quantitative phytochemical analyses of the extracts were determined using standard methods. RESULTS: H. gordonii extract demonstrated good inhibition against HIV RT with IC50 values of 73.55 ± 0.04 and 69.81 ± 9.45 µg/mL for ethanol and ethyl acetate extracts, respectively. Both extracts also demonstrated inhibitory activity against HIV PR with IC50 values of 97.29 ± 0.01 and 63.76 ± 9.01 µg/mL for ethanol and ethyl acetate extracts. In addition, H. gordonii also showed good antioxidant activity with IC50 values of 124.6 ± 11.3 and 126.2 ± 3.15 µg/mL obtained for ethanol and ethyl acetate extracts, respectively. The reducing power of H. gordonii extracts increased as the concentration increased which confirmed the presence of antioxidants (reductants) in the extracts. Phytochemical screening of H. gordonii revealed the presence of phenolics, alkaloids, terpenes, steroids, cardiac glycosides and tannins in the ethanolic extract, while the ethyl acetate extract only showed the presence of phenolics, cardiac glycosides and steroids. The total phenolic content was 420 ± 0.17 and 319.9 ± 0.2 mg GAE/g for the ethanol and ethyl acetate extracts, respectively. The ethanol extract, which revealed the presence of tannins, had a tannin content of 330 ± 0.2 mg TAE/g extract. CONCLUSION: This data suggests that H. gordonii has good in vitro inhibition against selected HIV-1 enzymes as well as antioxidant properties, suggesting new potential uses for this commercial plant.

Mammalian cell cultures as models for Mycobacterium tuberculosis-human immunodeficiency virus (HIV) interaction studies: A review.

Mycobacterium tuberculosis and human immunodeficiency virus (HIV) co-infections have remained a major public health concern worldwide, particularly in Southern Africa. Yet our understanding of the molecular interactions between the pathogens has remained poor due to lack of suitable preclinical models for such studies. We reviewed the use, this far, of mammalian cell culture models in HIV-MTB interaction studies. Studies have described the use of primary human cell cultures, including (1) monocyte-derived macrophage (MDM) fractions of peripheral blood mononuclear cell (PBMC), alveolar macrophages (AM), (2) cell lines such as the monocyte-derived macrophage cell line (U937), T lymphocyte cell lines (CEMx174, ESAT-6-specific CD4(+) T-cells) and an alveolar epithelial cell line (A549) and (3) special models such as stem cells, three dimensional (3D) or organoid cell models (including a blood-brain barrier cell model) in HIV-MTB interaction studies. The use of cell cultures from other mammals, including: mouse cell lines [macrophage cell lines RAW 264.7 and J774.2, fibroblast cell lines (NIH 3T3, C3H clones), embryonic fibroblast cell lines and T-lymphoma cell lines (S1A.TB, TIMI.4 and R1.1)]; rat (T cells: Rat2, RGE, XC and HH16, and alveolar cells: NR8383) and primary guinea pigs derived AMs, in HIV-MTB studies is also described. Given the spectrum of the models available, cell cultures offer great potential for host-HIV-MTB interactions studies.

The Potential of Sub-Saharan African Plants in the Management of Human Immunodeficiency Virus Infections: A Review.

Acquired immunodeficiency syndrome, caused by human immunodeficiency virus (HIV), is a leading cause of mortality and morbidity in Sub-Saharan Africa, particularly in Southern Africa. Phytomedicines are an integral part of African health care. The Southern African flora is composed of at least 23 400 taxa. Despite this richness, only a handful of botanical products have been assessed for activities against HIV. This study aimed to summarize the potential of Sub-Saharan African plants, based on their composition and the established bioactivities, as sources of agents to manage HIV symptoms and as retroviral therapy. At least 109 plant species from 42 families and 94 genera that are found in Southern Africa were shown to have potential or actual activities against HIV. Only 12 of these plant species from 6 families and 10 genera were shown to harbour anti-HIV properties. Phytochemicals that include ß-sitosterols, terpenoids, glycosides, saponins, flavonoids, triterpenoids, tannins and alkaloids, which harbour anti-HIV properties, were found to have a near cosmopolitan presence across the plant families in the region. Bioactivities of multiple phytochemicals are comparable to those for standard allopathic antiretroviral drugs. Research to determine the anti-HIV activities of the identified and other plants, including clinical trials, is long overdue.

Therapeutic and Prophylactic Potential of Morama (Tylosema esculentum): A Review.

Tylosema esculentum (morama) is a highly valued traditional food and source of medicine for the San and other indigenous populations that inhabit the arid to semi-arid parts of Southern Africa. Morama beans are a rich source of phenolic acids, flavonoids, certain fatty acids, non-essential amino acids, certain phytosterols, tannins and minerals. The plant's tuber contains griffonilide, behenic acid and starch. Concoctions of extracts from morama bean, tuber and other local plants are frequently used to treat diarrhoea and digestive disorders by the San and other indigenous populations. Information on composition and bioactivity of phytochemical components of T. esculentum suggests that the polyphenol-rich extracts of the bean testae and cotyledons have great potential as sources of chemicals that inhibit infectious microorganisms (viral, bacterial and fungal, including drug-resistant strains), offer protection against certain non-communicable diseases and promote wound healing and gut health. The potential antinutritional properties of a few morama components are also highlighted. More research is necessary to reveal the full prophylactic and therapeutic potential of the plant against diseases of the current century. Research on domestication and conservation of the plant offers new hope for sustainable utilisation of the plant.

Antioxidant and anti-inflammatory activity of Ocimum labiatum extract and isolated labdane diterpenoid.

BACKGROUND: Plants from the genus Ocimum are used as folk medicine for treating various diseases including inflammatory and immune-related diseases. Numerous reports have suggested plant extracts and their constituents as possible anti-inflammatory agents. Here, in vitro evidence of Ocimum labiatum's immune-enhancing and antioxidant properties is presented for the first time. METHODS: The anti-inflammatory effect of O. labiatum ethanolic extract and an isolated diterpenoid was determined using a cytometric bead array (CBA) technique. The effect on phytohemagglutinin (PHA)-induced nitric oxide (NO) production in peripheral blood mononuclear cells (PBMCs) was also assessed. A battery of antioxidant assays were used for detecting antioxidant activity while the anti-inflammatory mechanism was evaluated using an ELISA-based activator protein (AP-1) (c-Jun) assay. Cytotoxicity was determined on TZM-bl and PBMCs using a tetrazolium dye and confirmed by a novel label-free real-time assay. RESULTS: A 25 µg/mL non-cytotoxic concentration of O. labiatum extract significantly (p < 0.05) inhibited the production of pro-inflammatory cytokines; IL-2, IL-4, IL-6 and IL-17A. Except for the dual acting pro- or anti-inflammatory cytokine, IL-6, which was upregulated, a non-cytotoxic 50 µM concentration of the isolated labdane diterpenoid compound significantly (p < 0.05) decreased the production of all the pro-inflammatory cytokines. In the anti-inflammatory pathway studies, the compound also inhibited AP-1 significantly (p < 0.05) at 50 µM. The extract demonstrated strong, dose dependent antioxidant activity with IC50 values ranging from 13 ± 0.8 to 54.86 ± 1.28 µg/mL while the terpene had no antioxidant property. The extract and diterpenoid decreased the production of the inflammatory mediator NO, at non-cytotoxic concentrations. The CC50 of the extract in TZM-bl and PBMCs was 62.6 ± 0.6 and 30.1 ± 0.4 µg/mL while that of the compound was 112.6 ± 0.2 and 70 ± 0.4 µM respectively. The real time studies confirmed tetrazolium dye assessed viability and also detected a unique growth pattern for the plant materials compared to untreated cells. CONCLUSIONS: O. labiatum extract demonstrated promising anti-inflammatory and antioxidant properties while the terpenoid showed anti-inflammatory but no antioxidant activity. The anti-inflammatory mechanism of the terpene was a result of inhibition of AP-1. These data represents promising first steps towards the development of naturally derived anti-inflammation drugs.

Inhibition of HIV-1 enzymes, antioxidant and anti-inflammatory activities of Plectranthus barbatus.

ETHNOPHARMACOLOGICAL RELEVANCE: Plectranthus barbatus is widely used in African countries as an herbal remedy to manage HIV/AIDS and related conditions. AIM OF THE STUDY: To investigate the HIV-1 inhibitory, anti-inflammatory and antioxidant properties of P. barbatus and thereby provide empirical evidence for the apparent anecdotal success of the extracts. MATERIALS AND METHODS: Ethanolic extract of P. barbatus's leaves was screened against two HIV-1 enzymes: protease (PR) and reverse transcriptase (RT). Cytotoxicity of the extract was determined through measuring tetrazolium dye uptake of peripheral blood mononuclear cells (PBMCs) and the TZM-bl cell line. Confirmatory assays for cytotoxicity were performed using flow cytometry and real-time cell electronic sensing (RT-CES). The free radical scavenging activity of the extract was investigated with 2,2-diphenyl-1-picrylhydrazyl while the anti-inflammatory properties of the plant extract were investigated using a Th1/Th2/Th17 cytometric bead array technique. RESULTS: P. barbatus extract inhibited HIV-1PR and the 50% inhibitory concentration (IC50) was 62.0 µg/ml. The extract demonstrated poor inhibition of HIV-1 RT. Cytotoxicity testing presented CC50 values of 83.7 and 50.4 µg/ml in PBMCs and TZM-bl respectively. In addition, the extract stimulated proliferation in HIV negative and positive PBMCs treated. RT-CES also registered substantial TZM-bl proliferation after extract treatment. The extract exhibited strong antioxidant activity with an IC50 of 16 µg/ml and reduced the production of pro-inflammatory cytokines indicating anti-inflammatory potential. CONCLUSION: This is the first demonstration of the in vitro anti HIV-1 potential of P. barbatus including direct activity as well as through the stimulation of protective immune and inflammation responses. The low cytotoxicity of the extract is also in agreement with the vast anecdotal use of this plant in treating various ailments with no reported side-effects.

Tylosema esculentum (Marama) Tuber and Bean Extracts Are Strong Antiviral Agents against Rotavirus Infection.

Tylosema esculentum (marama) beans and tubers are used as food, and traditional medicine against diarrhoea in Southern Africa. Rotaviruses (RVs) are a major cause of diarrhoea among infants, young children, immunocompromised people, and domesticated animals. Our work is first to determine anti-RV activity of marama bean and tuber ethanol and water extracts; in this case on intestinal enterocyte cells of human infant (H4), adult pig (CLAB) and adult bovine (CIEB) origin. Marama cotyledon ethanolic extract (MCE) and cotyledon water extract (MCW) without RV were not cytotoxic to all cells tested, while seed coat and tuber extracts showed variable levels of cytotoxicity. Marama cotyledon ethanolic and water extracts (MCE and MCW, resp.) (≥0.1 mg/mL), seed coat extract (MSCE) and seed coat water extract (MSCW) (0.01 to 0.001 mg/mL), especially ethanolic, significantly increased cell survival and enhanced survival to cytopathic effects of RV by at least 100% after in vitro co- and pre-incubation treatments. All marama extracts used significantly enhanced nitric oxide release from H4 cells and enhanced TER (Ω/cm(2)) of enterocyte barriers after coincubation with RV. Marama cotyledon and seed coat extracts inhibited virion infectivity possibly through interference with replication due to accumulation of nitric oxide. Marama extracts are therefore promising microbicides against RV.