Phytochemical, pharmacological and toxicological aspects ofHibiscus sabdariffa L.: a review

Ethyl acetate fraction from Hibiscus sabdariffa L. attenuates diabetes-associated cognitive impairment in mice

The ameliorating effects of the ethyl acetate fraction from Hibiscus sabdariffa L. (EFHS)² against diabetes mellitus (DM)³ and DM-induced cognitive impairment were investigated on streptozotocin (STZ)⁴-induced DM mice. The EFHS groups showed improved hyperglycemia and glucose tolerance compared to the STZ group. Furthermore, their liver and kidney function and lipid metabolic imbalance in the blood serum were effectively recovered. The EFHS groups significantly ameliorated STZ-induced cognitive impairment in Y-maze, passive avoidance, and Morris water maze (MWM)⁵ tests. The EFHS groups showed significant improvement in the antioxidant and cholinergic systems of the brain tissue. In addition, EFHS had an excellent ameliorating effect on protein expression levels from the tau hyperphosphorylation pathways, such as phospho-c-Jun N-terminal kinases (p-JNK),⁶ phospho-tau (p-tau),⁷ and cleaved poly (ADP-ribose) polymerase (c-PARP).⁸ The main compounds of EFHS were identified as various phenolic compounds, including hibiscus acid, caffeoylquinic acid (CQA)⁹ isomers, and quercetin derivates. Therefore, EFHS containing various physiologically active materials can potentially be used for improving DM-induced cognitive impairment via its antioxidant activity, improvement of the cholinergic system, and hyperphosphorylation tau signaling.

Antihypertensive Effects of Roselle-Olive Combination in L-NAME-Induced Hypertensive Rats

This study aimed to evaluate the antihypertensive efficacy of a new combination therapy of Hibiscus sabdariffa and Olea europaea extracts (2 : 1; Roselle-Olive), using N(G)-nitro-L-arginine-methyl ester- (L-NAME-) induced hypertensive model. Rats received L-NAME (50 mg/kg/day, orally) for 4 weeks. Concurrent treatment with Roselle-Olive (500, 250, and 125 mg/kg/day for 4 weeks) resulted in a dose-dependent decrease in both systolic and diastolic blood pressure, reversed the L-NAME-induced suppression in serum nitric oxide (NO), and improved liver and kidney markers, lipid profile, and oxidative status. Furthermore, Roselle-Olive significantly lowered the elevated angiotensin-converting enzyme activity (ACE) and showed a marked genoprotective effect against oxidative DNA damage in hypertensive rats. Roselle-Olive ameliorated kidney and heart lesions and reduced aortic media thickness. Real-time PCR and immunohistochemistry showed an enhanced endothelial nitric oxide synthase (eNOS) gene and protein expression in both heart and kidney of Roselle-Olive-treated rats. To conclude, our data revealed that Roselle-Olive is an effective combination in which H. sabdariffa and O. europaea synergistically act to control hypertension. These effects are likely to be mediated by antioxidant and genoprotective actions, ACE inhibition, and eNOS upregulation by Roselle-Olive constituents. These findings provide evidences that Roselle-Olive combination affords efficient antihypertensive effect with a broad end-organ protective influence.

Ethnomedicinal, Phytochemical and Ethnopharmacological Aspects of Four Medicinal Plants of Malvaceae Used in Indian Traditional Medicines: A Review

The ethnomedicinal values of plants form the basis of the herbal drug industry. India has contributed its knowledge of traditional system medicines (Ayurveda and Siddha) to develop herbal medicines with negligible side effects. The World Health Organization has also recognized the benefits of drugs developed from natural products. Abutilon indicum, Hibiscus sabdariffa, Sida acuta and Sida rhombifolia are ethnomedicinal plants of Malvaceae, commonly used in Indian traditional system of medicines. Traditionally these plants were used in the form of extracts/powder/paste by tribal populations of India for treating common ailments like cough and cold, fever, stomach, kidney and liver disorders, pains, inflammations, wounds, etc. The present review is an overview of phytochemistry and ethnopharmacological studies that support many of the traditional ethnomedicinal uses of these plants. Many phytoconstituents have been isolated from the four ethnomedicinal plants and some of them have shown pharmacological activities that have been demonstrated by in vivo and/or in vitro experiments. Ethnomedicinal uses, supported by scientific evidences is essential for ensuring safe and effective utilization of herbal medicines.

Efficacy of standardized extract of Hibiscus sabdariffa L. (Malvaceae) in improving iron status of adults in malaria endemic area: A randomized controlled trial

ETHNOPHARMACOLOGICAL RELEVANCE

Indigenous community of Mkuranga district have been using aqueous extract of H. sabdariffa L. for treating anemia. However, there have been neither safety nor efficacy studies to validate this medicinal product in anemia.

AIM

The purpose of this study was to establish efficacy and safety of standardized aqueous extract of H. sabdariffa L. in anemic adults.

MATERIALS AND METHODS

This was a randomized controlled clinical trial in which 130 adults' men and women aged 18-50 years were involved after meeting the inclusion criteria. Initially, standardized aqueous extract of H. sabdariffa L. was prepared using optimized extraction parameters. Stratified randomization was used to randomize participants into four fixed dose groups. The first group received oral dose of 1000ml while the 2nd group was randomized to receive 1500ml orally. The last two groups were given a dose of 2000ml of extract and 200mg ferrous sulphate tablet respectively. Primary endpoint was the actual change of iron status indicators at the end of 30 days follow up period as compared to those recorded at baseline. Adverse effects were assessed at every 10th day scheduled visit. In all arms, HB and hematopoietic parameters were measured using HemoCue hemoglobinometer® (HemoCue, Ängelholm, Sweden) and hematology analyzer® respectively at the trial site. Follow up was done for 30 days. A total of 82 participants were included for analysis.

RESULTS

A standardized aqueous extract of H. sabdariffa L. did not improve iron status in anemic adults in malaria endemic region (P>0.005). However, there was evidence to support the safety of the extract for human consumptions as herbal supplement. Iron and organic acids contents of H. sabdariffa L. extract showed the potential of improving hematopoietic parameters. Studies with bigger sample size are therefore needed to establish the efficacy of the extract when concurrently used with malaria chemoprophylaxis in malaria endemic areas.

Crystal structures of hibiscus acid and hibiscus acid dimethyl ester isolated from Hibiscus sabdariffa (Malvaceae)

The biologically active title compounds have been isolated from Hibiscus sabdariffa plants, hibiscus acid as a dimethyl sulfoxide monosolvate [systematic name: (2S,3R)-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carb-oxy-lic acid dimethyl sulfoxide monosolvate], C6H6O7·C2H6OS, (I), and hibiscus acid dimethyl ester [systematic name: dimethyl (2S,3R)-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carboxyl-ate], C8H10O7, (II). Compound (I) forms a layered structure with alternating layers of lactone and solvent mol-ecules, that include a two-dimensional hydrogen-bonding construct. Compound (II) has two crystallographically independent and conformationally similar mol-ecules per asymmetric unit and forms a one-dimensional hydrogen-bonding construct. The known absolute configuration for both compounds has been confirmed.

Antibacterial activities of medicinal plants used in Mexican traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

We provide an extensive summary of the in vitro antibacterial properties of medicinal plants popularly used in Mexico to treat infections, and we discuss the ethnomedical information that has been published for these species.

MATERIALS AND METHODS

We carried out a bibliographic investigation by analyzing local and international peer-reviewed papers selected by consulting internationally accepted scientific databases from 1995 to 2014. We provide specific information about the evaluated plant parts, the type of extracts, the tested bacterial strains, and the inhibitory concentrations for each one of the species. We recorded the ethnomedical information for the active species, as well as their popular names and local distribution. Information about the plant compounds that has been identified is included in the manuscript. This review also incorporates an extensive summary of the available toxicological reports on the recorded species, as well as the worldwide registries of plant patents used for treating bacterial infections. In addition, we provide a list with the top plant species with antibacterial activities in this review RESULTS: We documented the in vitro antibacterial activities of 343 plant species pertaining to 92 botanical families against 72 bacterial species, focusing particularly on Staphylococcus aureus, Mycobacterium tuberculosis, Escherichia coli and Pseudomonas aeruginosa. The plant families Asteraceae, Fabaceae, Lamiaceae and Euphorbiaceae included the largest number of active species. Information related to popular uses reveals that the majority of the plants, in addition to treating infections, are used to treat other conditions. The distribution of Mexican plants extended from those that were reported to grow in just one state to those that grow in all 32 Mexican states. From 75 plant species, 225 compounds were identified. Out of the total plant species, only 140 (40.57%) had at least one report about their toxic effects. From 1994 to July 2014 a total of 11,836 worldwide antibacterial patents prepared from different sources were recorded; only 36 antibacterial patents from plants were registered over the same time period. We offered some insights on the most important findings regarding the antibacterial effects, current state of the art, and research perspectives of top plant species with antibacterial activities in vitro.

CONCLUSIONS

Studies of the antibacterial in vitro activity of medicinal plants popularly used in Mexico to treat infections indicate that both the selection of plant material and the investigation methodologies vary. Standardized experimental procedures as well as in vivo pharmacokinetic studies to document the effectiveness of plant extracts and compounds are necessary. This review presents extensive information about the medicinal plants possessing antibacterial activity that has been scientifically studied and are popularly used in Mexico. We anticipate that this review will be of use for future studies because it constitutes a valuable information tool for selecting the most significant plants and their potential antibacterial properties.

Herbal products containing Hibiscus sabdariffa L., Crataegus spp., and Panax spp.: Labeling and safety concerns

Herbs have been used from ancient times for infusion preparation based on their potential health effects. In particular, the consumption of Hibiscus sabdariffa L., Crataegus spp. and Panax spp. has been largely associated to cardiovascular benefits. In this work, the label information of 52 herbal products for infusion preparation containing the referred herbs was analyzed and discussed, taking into consideration the European Union regulation for herbal products, which intends to protect public health and harmonize the legal framework in Member States. Details about the cardiovascular-related statements and warning notifications about consumption were considered. Also, regulatory issues and possible herb-drug interactions were explored and discussed. A total of 14 of the 52 herbal products selected presented health claims/statements on the label. Hibiscus was present in the majority of the products and, in some cases, it was mentioned only in the ingredients list and not on the product front-of-pack. Despite the promising outcomes of these plants to modulate cardiovascular risk markers, consumers with some sort of cardiovascular dysfunction and/or under medication treatments should be aware to carefully analyze the labels and consult additional information related to these herbal products. Manufacturers have also a huge responsibility to inform consumers by presenting awareness statements. Lastly, health professionals must advise and alert their patients about possible interactions that could occur between the concomitant consumption of drugs and herbs. Overall, there is still a real need of additional studies and clinical trials to better understand herbs effects and establish a science-based guidance to assess their safety.

Effect of aqueous extract and anthocyanins of calyces of Hibiscus sabdariffa (Malvaceae) in rats with adenine-induced chronic kidney disease

OBJECTIVES

The aim of this work was to assess the possible beneficial effects of aqueous extracts of Hibiscus sabdariffa L. calyces and anthocyanins isolated therefrom in an adenine-induced chronic kidney disease (CKD) model.

METHODS

Rats were orally given, for 28 consecutive days, either adenine alone or together with either aqueous extract of H. sabdariffa calyces (5 and 10%) or anthocyanins (50, 100 and 200 mg/kg of anthocyanin concentrate). For comparative purposes, two groups of rats were given lisinopril (10 mg/kg).

KEY FINDINGS

When either H. sabdariffa aqueous extract or the anthocyanins isolated from it was administered along with adenine, the adverse effects of adenine-induced CKD were significantly lessened, mostly in a dose-dependent manner. The positive effects were similar to those obtained by administration of lisinopril.

CONCLUSIONS

The results obtained show that both H. sabdariffa and its anthocyanins could be considered as possible promising safe dietary agents that could be used to attenuate the progression of human CKD. This could have added significance as H. sabdariffa tea is widely consumed in many parts of Africa and Asia and is thus readily available.

Anthocyanins from roselle extract arrest cell cycle G2/M phase transition via ATM/Chk pathway in p53-deficient leukemia HL-60 cells

Cell cycle regulation is an important issue in cancer therapy. Delphinidin and cyanidin are two major anthocyanins of the roselle plant (Hibiscus sabdariffa). In the present study, we investigated the effect of Hibiscus anthocyanins (HAs) on cell cycle arrest in human leukemia cell line HL-60 and the analyzed the underlying molecular mechanisms. HAs extracted from roselle calyces (purity 90%) markedly induced G2/M arrest evaluated with flow cytometry analysis. Western blot analyses revealed that HAs (0.1-0.7 mg mL^-1 ) induced G2/M arrest via increasing Tyr15 phosphorylation of Cdc2, and inducing Cdk inhibitors p27 and p21. HAs also induced phosphorylation of upstream signals related to G2/M arrest such as phosphorylation of Cdc25C tyrosine phosphatase at Ser216, increasing the binding of pCdc25C with 14-3-3 protein. HAs-induced phosphorylation of Cdc25C could be activated by ATM checkpoint kinases, Chk1, and Chk2. We first time confirmed that ATM-Chk1/2-Cdc25C pathway as a critical mechanism for G2/M arrest in HAs-induced leukemia cell cycle arrest, indicating that this compound could be a promising anticancer candidate or chemopreventive agents for further investigation. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1290-1304, 2017.

Hibiscus Sabdariffa L. Flowers and Olea Europea L. Leaves Extract-Based Formulation for Hypertension Care: In Vitro Efficacy and Toxicological Profile

Olea europaea L. leaves extract (Oe) and Hybiscus sabdariffa L. flowers extract (Hs) have calcium antagonistic properties. Aim of this work was to study the cardiovascular effects of Pres Phytum(®), a nutraceutical formulation containing a mixture of the two extracts and the excipients, and investigate its possible off-target effects, using in vitro biological assays on guinea pig isolated organs. Cardiovascular effects were assessed using guinea pig atria and aorta. The effects of Pres Phytum on spontaneous gastrointestinal, urinary, and respiratory tracts smooth muscle contractility were evaluated. Pres Phytum exerted a vasorelaxant effect (IC50 = 2.38 mg/mL) and a negative chronotropic effect (IC50 = 1.04 mg/mL) at concentrations lower than those producing smooth muscle spontaneous contractility alterations in the other organs. Compared to Pres Phytum, the mixture did not exert negative inotropic activity, while it maintained a negative chronotropic efficacy (IC50 = 1.04 mg/mL). These experimental data suggest a possible nutraceutical use of this food supplement for the management of preclinical hypertension.

Purification, characterization and immunoregulatory activity of a polysaccharide isolated from Hibiscus sabdariffa L

BACKGROUND

Hibiscus sabdariffa L. is not only used traditionally as a component of herbal drinks, beverages and flavoring agents but also as a herbal medicine in the drug industry. Bioactive polysaccharides are important constituents of H. sabdariffa that may contribute to the plant's beneficial effects. This study was designed to investigate the structural characteristics of a water-soluble polysaccharide from H. sabdariffa, HSP41, and its immunoregulatory activity on RAW264.7 cells.

RESULTS

HSP41 was mainly composed of arabinose, xylose and mannose at a molar ratio of 1:1.34:15.6, with an average molecular weight of 3.3 × 10⁵  Da. Fourier transform infrared (FTIR) spectra exhibited absorption peaks characteristic of HSP41. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed the amorphous form and aggregation conformation of HSP41 respectively. HSP41 significantly induced interleukin 1β (IL-1β) and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells in vitro, promoting an increase in nuclear factor kB p65 (NF-kB p65) levels in the nucleus.

CONCLUSION

The results indicated that HSP41 up-regulated the immune response by stimulating RAW264.7 cell activity. HSP41, a promising immunoregulator, possibly contributes to the health benefits of H. sabdariffa and might have potential applications in health food or medicine. © 2016 Society of Chemical Industry.

Antrodia cinnamomea Prevents Obesity, Dyslipidemia, and the Derived Fatty Liver via Regulating AMPK and SREBP Signaling

Antrodia cinnamomea (AC), a protogenic fungus that only grows on the heartwood of endemic Cinnamomum kanehirae Hayata in Taiwan, is used to treat a variety of illness including liver disease. However, little is known about the benefit of AC against obesity and the related hepatic disorder. Using high-fat-diet (HFD) feed mice, we aimed to investigate whether the extract of AC (ACE) could reduce excessive weight, body fat, and serum lipids and prevent the development of non-alcoholic fatty liver (NAFLD). C57BL/6 mice were divided into five groups fed with different diets: control, HFD, and HFD with 0.5%, 1%, or 2% of ACE, respectively. After 10 weeks the animals were sacrificed, with serum and liver collected. HFD-induced elevation of body weight gain, body fat deposition, and serum free fatty acid (FFA), triacylglycerol (TGs), total cholesterol, and ratio of LDL cholesterol (LDL-C)/HDL cholesterol (HDL-C), were significantly restored by ACE. ACE reduced aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hepatic lipid deposits increased by HFD. ACE increased p-AMP activated protein kinase (pAMPK) but decreased Sterol regulatory element binding protein (SREBP), fatty acid synthase (FAS), 1-acylglycerol-3-phosphate acyltransferase (AGPAT), and 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase. The chemical analysis reveals ACE is full of triterpenes, the most abundant of which is Antcin K, followed by sulphurenic acid, eburicoic acid, antcin C, dehydrosulphurenic acid, antcin B, and propanoic acid. In conclusion, ACE should be used to prevent obesity and derived fatty liver. The applicability of ACE on NAFLD deserves further investigation.

Biofabrication of Fe nanoparticles in aqueous extract of Hibiscus sabdariffa with enhanced photocatalytic activities

Hibiscus sabdariffa is a strongly basic dye with a large number of medicinal applications and is used for various diagnostic purposes.

Preparation and Validated Analysis of Anthocyanin Concentrate from the Calyces of Hibiscus sabdariffa

Extracts of Hibiscus sabdariffa calyces have been shown to have various medicinal properties, some of which have been reported to be due to anthocyanins present in the calyces. To study whether these claims are valid, it is necessary to produce an extract with a high anthocyanin content and to have available a method to identify and quantify the individual compounds in the product. A method of extraction and purification has been developed based on a polyamide column chromatographic purification step. Using this method, anthocyanin concentrates were produced containing from 57 to 64% of delphinidin-3-sambubioside plus cyanidin-3-sambubioside. A rapid, efficient and validated HPLC analytical method was developed and used for the analysis of the anthocyanin concentrate.

Identification and Characterization of Roseltide, a Knottin-type Neutrophil Elastase Inhibitor Derived from Hibiscus sabdariffa

Plant knottins are of therapeutic interest due to their high metabolic stability and inhibitory activity against proteinases involved in human diseases. The only knottin-type proteinase inhibitor against porcine pancreatic elastase was first identified from the squash family in 1989. Here, we report the identification and characterization of a knottin-type human neutrophil elastase inhibitor from Hibiscus sabdariffa of the Malvaceae family. Combining proteomic and transcriptomic methods, we identified a panel of novel cysteine-rich peptides, roseltides (rT1-rT8), which range from 27 to 39 residues with six conserved cysteine residues. The 27-residue roseltide rT1 contains a cysteine spacing and amino acid sequence that is different from the squash knottin-type elastase inhibitor. NMR analysis demonstrated that roseltide rT1 adopts a cystine-knot fold. Transcriptome analyses suggested that roseltides are bioprocessed by asparagine endopeptidases from a three-domain precursor. The cystine-knot structure of roseltide rT1 confers its high resistance against degradation by endopeptidases, 0.2 N HCl, and human serum. Roseltide rT1 was shown to inhibit human neutrophil elastase using enzymatic and pull-down assays. Additionally, roseltide rT1 ameliorates neutrophil elastase-stimulated cAMP accumulation in vitro. Taken together, our findings demonstrate that roseltide rT1 is a novel knottin-type neutrophil elastase inhibitor with therapeutic potential for neutrophil elastase associated diseases.

Antitumoral Effect of Hibiscus sabdariffa on Human Squamous Cell Carcinoma and Multiple Myeloma Cells

Cancer is a leading cause of death worldwide. Despite therapeutic improvements, some cancers are still untreatable. Recently there has been an increasing interest in the use of natural substances for cancer prevention and treatment. Hibiscus sabdariffa (HS) is a plant, belonging to Malvaceae family, widespread in South Asia and Central Africa. HS extract (HSE) used in folk medicine, gained researchers' interest thanks to its antioxidant, anti-inflammatory, and chemopreventive properties. In the present study, we initially assessed HSE effect on a panel of human tumor cell lines. Then we focused our study on the following that are most sensitive to HSE action cell lines: Multiple Myeloma (MM) cells (RPMI 8226) and Oral Squamous Cell Carcinoma (OSCC) cells (SCC-25). In both RPMI 8226 and SCC-25 cells, HSE impaired cell growth, exerted a reversible cytostatic effect, and reduced cell motility and invasiveness. We evaluated the involvement of MAPKs ERK1/2 and p38 in HSE effects by using specific inhibitors, U0126 and SB203580, respectively. For both SCC-25 and RPMI 8226, HSE cytostatic effect depends on p38 activation, whereas ERK1/2 modulation is crucial for cell motility and invasiveness. Our results suggest that HSE may be a potential therapeutic agent against MM and OSCC.

Aqueous Extracts of Hibiscus sabdariffa Calyces to Control Aichi Virus

Aqueous Hibiscus sabdariffa extracts possess antimicrobial properties with limited information available on their antiviral effects. Aichi virus (AiV) is an emerging foodborne pathogen that causes gastroenteritis. Vaccines are currently unavailable to prevent their disease transmission. The objective of this study was to determine the antiviral effects of aqueous H. sabdariffa extracts against AiV. AiV at ~5 log PFU/ml was incubated with undiluted (200 mg/ml), 1:1 (100 mg/ml) or 1:5 (40 mg/ml) diluted aqueous hibiscus extract (pH 3.6), phosphate-buffered saline (pH 7.2 as control), or malic acid (pH 3.0, acid control) at 37 °C over 24 h. Treatments were stopped by serially diluting in cell-culture media containing fetal bovine serum and titers were determined using plaque assays on confluent Vero cells. Each treatment was replicated thrice and assayed in duplicate. AiV did not show any significant reduction with 1:1 (100 mg/ml) or 1:5 (40 mg/ml) diluted aqueous hibiscus extracts or malic acid after 0.5, 1, or 2 h at 37 °C. However, AiV titers were reduced to non-detectable levels after 24 h with all the three tested concentrations, while malic acid showed only 0.93 log PFU/ml reduction after 24 h. AiV was reduced by 0.5 and 0.9 log PFU/ml with undiluted extracts (200 mg/ml) after 2 and 6 h, respectively. AiV treated with 1:1 (100 mg/ml) and 1:5 (40 mg/ml) diluted extracts showed a minimal ~0.3 log PFU/ml reduction after 6 h. These extracts show promise to reduce AiV titers mainly through alteration of virus structure, though higher concentrations may have improved effects.

Evaluation of the effects of roselle (Hibiscus sabdariffa L.) on oxidative stress and serum levels of lipids, insulin and hs-CRP in adult patients with metabolic syndrome: a double-blind placebo-controlled clinical trial

BACKGROUND

Roselle (Hibiscus sabdariffa L.) is a plant with antihyperlipidemic and antihypertensive effects. This study aimed to evaluate the effects of roselle calyces on the serum levels of lipids and insulin, inflammation, and oxidative stress in patients with metabolic syndrome (MetS).

METHODS

Forty adult patients with MetS were randomly assigned to receive either 500 mg of H. sabdariffa calyx powder or placebo once daily for 4 weeks. Systolic and diastolic blood pressures (SBP and DBP) and BMI (body mass index) as well as fasting serum levels of glucose (FPG; fasting plasma glucose), insulin, lipoproteins, triglycerides (TG), high-sensitivity C-reactive protein (hs-CRP), and malondialdehyde (MDA) were determined pre- and post-intervention and compared.

RESULTS

H. sabdariffa significantly reduced serum TG (p=0.044) and SBP (p=0.049) compared to placebo. All other variables were not significantly affected by the interventions.

CONCLUSIONS

Daily consumption of 500 mg of H. sabdariffa L. calyx powder can decrease SBP and serum TG in MetS patients.

Anti-hypertensive Herbs and their Mechanisms of Action: Part I

The use of herbal therapies for treatment and management of cardiovascular diseases (CVDs) is increasing. Plants contain a bounty of phytochemicals that have proven to be protective by reducing the risk of various ailments and diseases. Indeed, accumulating literature provides the scientific evidence and hence reason d'etre for the application of herbal therapy in relation to CVDs. Slowly, but absolutely, herbal remedies are being entrenched into evidence-based medical practice. This is partly due to the supporting clinical trials and epidemiological studies. The rationale for this expanding interest and use of plant based treatments being that a significant proportion of hypertensive patients do not respond to Modern therapeutic medication. Other elements to this equation are the cost of medication, side-effects, accessibility, and availability of drugs. Therefore, we believe it is pertinent to review the literature on the beneficial effects of herbs and their isolated compounds as medication for treatment of hypertension, a prevalent risk factor for CVDs. Our search utilized the PubMed and ScienceDirect databases, and the criterion for inclusion was based on the following keywords and phrases: hypertension, high blood pressure, herbal medicine, complementary and alternative medicine (CAM), nitric oxide, vascular smooth muscle cell (VSMC) proliferation, hydrogen sulfide, nuclear factor kappa-B, oxidative stress, and epigenetics/epigenomics. Each of the aforementioned keywords was co-joined with herb in question, and where possible with its constituent molecule(s). In this first of a two-part review, we provide a brief introduction of hypertension, followed by a discussion of the molecular and cellular mechanisms. We then present and discuss the plants that are most commonly used in the treatment and management of hypertension.

Phenolic compounds of Hibiscus sabdariffa and influence of organic residues on its antioxidant and antitumoral properties

The aim of this study was to evaluate the phenolic and flavonoids contents and the antioxidant and antitumoral activity of leaf and calyx methanolic extracts from Hibiscus sabdariffa (roselle) cultivated with poultry litter and organosuper® under three modes of application. The total phenolic content in the each extract was determined using the Folin-Ciocalteu reagent and for aluminium chloride flavonoids. The antioxidant parameters were analyzed using a 2, 2-diphenyl-1-picrylhydrazyl (DPPH.) free radical scavenging assay. An antitumor colorimetric assay using sulforhodamine B. The highest contents of phenolic and flavonoids were observed in leaf extracts (389.98 and 104.52 mg g-1, respectively) and calyx extracts (474.09 and 148.35 mg g-1, respectively) from plants cultivated with organosuper®, although these values did not differ significantly from those observed for the other treatments. The average IC50 of leaves (43.48 μg mL-1) and calyces (37.15 μg mL-1) demonstrated that both have substances that may contribute to free radical scavenging action. The methanol extract from calyces showed significant selective activity against a leukemia line (K-562), with IC50 values of 0.12 mg mL-1 (organosuper®) and 1.16 mg mL-1 (poultry litter), with concentration-dependent, cytotoxic and cytocidal effects.

Aqueous Extracts of Hibiscus sabdariffa Calyces Decrease Hepatitis A Virus and Human Norovirus Surrogate Titers

Hibiscus sabdariffa extract is known to have antioxidant, anti-diabetic, and antimicrobial properties. However, their effects against foodborne viruses are currently unknown. The objective of this study was to determine the antiviral effects of aqueous extracts of H. sabdariffa against human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and hepatitis A virus (HAV) at 37 °C over 24 h. Individual viruses (~5 log PFU/ml) were incubated with 40 or 100 mg/ml of aqueous hibiscus extract (HE; pH 3.6), protocatechuic acid (PCA; 3 or 6 mg/ml, pH 3.6), ferulic acid (FA; 0.5 or 1 mg/ml; pH 4.0), malic acid (10 mM; pH 3.0), or phosphate buffered saline (pH 7.2 as control) at 37 °C over 24 h. Each treatment was replicated thrice and plaque assayed in duplicate. FCV-F9 titers were reduced to undetectable levels after 15 min with both 40 and 100 mg/ml HE. MNV-1 was reduced by 1.77 ± 0.10 and 1.88 ± 0.12 log PFU/ml after 6 h with 40 and 100 mg/ml HE, respectively, and to undetectable levels after 24 h by both concentrations. HAV was reduced to undetectable levels by both HE concentrations after 24 h. PCA at 3 mg/ml reduced FCV-F9 titers to undetectable levels after 6 h, MNV-1 by 0.53 ± 0.01 log PFU/ml after 6 h, and caused no significant change in HAV titers. FA reduced FCV-F9 to undetectable levels after 3 h and MNV-1 and HAV after 24 h. Transmission electron microscopy showed no conclusive results. The findings suggest that H. sabdariffa extracts have potential to prevent foodborne viral transmission.

In vitro Antibacterial Activity of Aqueous and Ethanol Extracts of Aristolochia indica and Toddalia asiatica Against Multidrug-Resistant Bacteria

Bacteria have developed multidrug resistance against available antimicrobial agents. Infectious diseases caused by these multidrug-resistant bacteria are major causes of morbidity and mortality in human beings. Synthetic drugs are expensive and inadequate for the treatment of diseases, causing side effects and ineffective against multidrug-resistant bacteria. The medicinal plants are promising to have effective antimicrobial property due to presence of phytochemical compounds like alkaloids, flavanoids, tannins and phenolic compounds. The present study aimed to find the antimicrobial activity of medicinal plants against multidrug-resistant bacteria. Multidrug-resistant bacteria were identified by Kirby-Bauer disc diffusion method. Production of β-lactamases (extended spectrum β-lactamases, metallo β-lactamase and AmpC β-lactamase) were identified by combination disc method. Antibacterial activity of aqueous and ethanol extract of Aristolochia indica and Toddalia asiatica were detected by agar well diffusion assay and minimum inhibitory concentration. All bacteria used in this study showed antibiotic resistance to ≥3 antibiotics. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis and Vibrio cholerae were found to be positive for β-lactamase production. Ethanol extract of Aristolochia indica showed more significant antibacterial activity against multidrug-resistant bacteria than Toddalia asiatica. Ethanol extracts of Aristolochia indica and Toddalia asiatica showed minimum inhibitory concentration values of 50-100 μg/ml and 100-200 μg/ml, respectively against multidrug-resistant bacteria. From this study, it was concluded that Aristolochia indica has more potential to treat multidrug-resistant bacteria than Toddalia asiatica.

Variations in chemical fingerprints and major flavonoid contents from the leaves of thirty-one accessions of Hibiscus sabdariffa L

The leaves of Hibiscus sabdariffa L. have been used as traditional folk medicines for treating high blood pressure and fever. There are many accessions of H. sabdariffa L. throughout the world. To assess the chemical variations of 31 different accessions of H. sabdariffa L., fingerprinting analysis and quantitation of major flavonoids were performed by high‐performance liquid chromatography (HPLC). The HPLC method was validated for linearity, sensitivity, precision, repeatability and accuracy. A quadrupole‐time‐of‐flight mass spectrometry (Q‐TOF‐MS) was applied for the characterization of major compounds. A total of 9 compounds were identified, including 6 flavonoids and 3 phenolic acids. In the fingerprint analysis, similarity analysis (SA) and principal component analysis (PCA) were used to differentiate the 31 accessions of H. sabdariffa L. Based on the results of PCA and SA, the samples No. 15 and 19 appeared much different from the main group. The total content of five flavonoids varied greatly among different accessions, ranging from 3.35 to 23.30 mg/g. Rutin was found to be the dominant compound and the content of rutin could contribute to chemical variations among different accessions. This study was helpful to understand the chemical variations between different accessions of H. sabdariffa L., which could be used for quality control. © 2015 The Authors Biomedical Chromatography Published by John Wiley & Sons Ltd.

Volatiles and primary metabolites profiling in two Hibiscus sabdariffa (roselle) cultivars via headspace SPME-GC-MS and chemometrics

Hibiscus sabdariffa (roselle) is a plant of considerable commercial importance worldwide as functional food due to its organic acids, mucilage, anthocyanins, macro and micro-nutrients content. Although Hibiscus flowers are emerging as very competitive targets for phytochemical studies, very little is known about their volatile composition and or aroma, such knowledge can be suspected to be relevant for understanding its olfactory and taste properties. To provide insight into Hibiscus flower aroma composition and for its future use in food and or pharmaceutical industry, volatile constituents from 2 cultivars grown in Egypt, viz. Aswan and Sudan-1 were profiled using solid-phase microextraction (SPME) coupled to GCMS. A total of 104 volatiles were identified with sugar and fatty acid derived volatiles amounting for the major volatile classes. To reveal for cultivar effect on volatile composition in an untargeted manner, multivariate data analysis was applied. Orthogonal projection to latent structures-discriminant analysis (OPLS-DA) revealed for 1-octen-3-ol versus furfural/acetic acid enrichment in Aswan and Sudan-1 cvs., respectively. Primary metabolites contributing to roselle taste and nutritional value viz. sugars and organic acids were profiled using GC-MS after silylation. The impact of probiotic bacteria on roselle infusion aroma profile was further assessed and revealed for the increase in furfural production with Lactobacillus plantarum inoculation and without affecting its anthocyanin content. This study provides the most complete map for volatiles, sugars and organic acids distribution in two Hibiscus flower cultivars and its fermented product.

Permeability Study of Polyphenols Derived from a Phenolic-Enriched Hibiscus sabdariffa Extract by UHPLC-ESI-UHR-Qq-TOF-MS

Previous findings on the capacity of Hibiscus sabdariffa (HS) polyphenols to ameliorate metabolic disturbances justify the necessity of studies oriented to find the potential metabolites responsible for such an effect. The present study examined the intestinal epithelial membrane permeability of polyphenols present in a phenolic-enriched Hibiscus sabdariffa extract (PEHS), free and encapsulated, using the Caco-2 cell line. Additionally, selected polyphenols (quercetin, quercetin-3-glucoside, quercetin-3-glucuronide, and N-feruloyltyramine) were also studied in the same absorption model. The powerful analytical platform used ultra-high-performance liquid chromatography coupled with ultra-high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-ESI-UHR-Qq-TOF-MS), and enabled the characterization of seven new compounds in PEHS. In the permeation study, only a few compounds were able to cross the cell monolayer and the permeability was lower when the extract was in an encapsulated form. Pure compounds showed a moderate absorption in all cases. Nevertheless, these preliminary results may need further research to understand the complete absorption mechanism of Hibiscus polyphenols.

Isolation and Identification of an Allelopathic Substance from Hibiscus sabdariffa

In this study, an allelopathic substance was isolated from an aqueous methanol extract of Hibiscus sabdariffa L. by column chromatography and reverse phase HPLC. The chemical structure of the substance was determined by 1H NMR spectroscopy and mass spectrometry as trimethyl allo-hydroxycitrate. Trimethyl allo-hydroxycitrate inhibited the growth of cress hypocotyls and roots at concentrations greater than 10 mM. The concentrations required for 50% growth inhibition of the hypocotyls and roots of cress were 20.3 and 14.4 mM, respectively. The inhibitory activity of trimethyl allo-hydroxycitrate suggests that the substance may act as an allelopathic substance of H. sabdariffa.

Anthocyanin-rich extract from Hibiscus sabdariffa calyx counteracts UVC-caused impairments in rats

CONTEXT

Ultraviolet radiation (UV) was reported to cause oxidative stress. Hibiscus sabdariffa L. (Malvaceae) calyx is commonly used in traditional Asian and African medicines and possesses strong antioxidant capacity due to its anthocyanin (ANTH) content.

OBJECTIVE

This study researched the possible protective role of Hibiscus sabdariffa calyx extract (HSCE) in UVC exposure of rats.

MATERIAL AND METHODS

Levels of serum enzymes, renal function tests, and some oxidant/antioxidant biomarkers of skin, lens, and retina tissues were monitored. Rats were exposed to UVC 4 h daily for 40 d and simultaneously received HSCE containing 2.5, 5, and 10 mg doses of ANTH in drinking water.

RESULTS

Significant (p < 0.05) increases in the levels of serum aminotransferases, lactate dehydrogenase, urea, creatinine, and uric acid were noted after UVC exposure. In skin, lens, and retina tissues, total oxidant status, oxidative stress index, lipid peroxidation, and protein oxidation escalated markedly (p < 0.05) whereas total antioxidant status, reduced glutathione, and superoxide dismutase decreased dramatically (p < 0.05) related to UVC. Co-administration of HSCE with each ANTH dose significantly (p < 0.05) reversed aforementioned parameters (except total oxidant status) almost in all tissues. The LD50 of HSCE in rats was determined to be above 5000 mg/kg.

DISCUSSION AND CONCLUSION

Our data revealed that HSCE has a remarkable potential to counteract UVC-caused impairments, probably through its antioxidant and free radical-defusing effects. Therefore, HSCE could be useful against some cutaneous and ocular diseases in which UV and oxidative stress have a role in the etiopathogenesis.

Anthocyanins of Hibiscus sabdiffera Calyces from Sudan

Extracts of the calyces of Hibiscus sabdariffa are widely used in folk medicine to combat many illnesses. The active constituents of the extracts have been shown on several occasions to be anthocyanins. In our current studies the biological activities of an extract of H. sabdariffa calyces purchased in Oman, but grown in Sudan, are being compared with those of the anthocyanins isolated from them, and, for this, the anthocyanin profile of the extract needed to be ascertained. Although several anthocyanins were detected by UHPLC-ESI-MS/MS, delphinidin-3-sambubioside (major) and cyanidin-3-sambubioside were predominant.

Ethno-medicinal knowledge and plants traditionally used to treat anemia in Tanzania: a cross sectional survey

ETHNOPHARMACOLOGICAL RELEVANCE

Indigenous communities have often served as rich repositories of empirical knowledge on medicinal plants used for anemia. Use of these plants need to be validated with respect to their efficacy and safety so as to provide scientific basis of their use. Quantifying presence of medicinal plants used for anemia treatment, validating indigenous knowledge and extent of its use in rural Mkuranga district, Tanzania is the main focus of this paper.

METHODS

A cross sectional study conducted in May and December 2013 at Mkuranga District of Coastal region of Tanzania. Forty key informants including traditional healers, religious leaders, community members and healthcare workers were interviewed using semi structured questionnaire. Eight focus group discussions were also conducted. Both interviews and focus group discussion gathered data on socio-demographics, general knowledge of anemia and plants used to correct anemia. In a brief field visit, all plants mentioned during the interview were collected and later identified. Both NVivo 10 and STATA softwares were employed for statistical analysis.

RESULTS

Out of 40 participants, 31 were traditional healers, majority were male (77.4%). Mean age of the participants was 55.7±15 years. About 45% had no any formal education and majority (80%) were married. Twenty eight plant species are used to treat anemia. Hibiscus sabdariffa was the most mentioned species. The species belongs to 24 families, with Euphorbiaceae (14.3%) having the largest number. Lawsonia inermis, Aloe sp, Uvaria acuminata, Parinari curatellifolia, Ozoroa reticulata, Manihot esculenta, Canthium sp and Afzelia quanzensis were the plant species in which their claimed use for anemia were novel.

CONCLUSIONS

People in rural areas of Mkuranga district possess a rich traditional knowledge of medicinal plants species for anemia treatment. Researches on these plants showed promising anti-anemic activity. Analysis and documentation of this knowledge has not only helped the analysis and recognition of novel information, it also contributed to conserving it for future generations.

An anthocyanin-rich extract from Hibiscus sabdariffa linnaeus inhibits N-nitrosomethylurea-induced leukemia in rats

A previous study reported that anthocyanins from roselle (Hibiscus sabdariffa L.) showed significant anticancer activity in human promyelocytic leukemia cells. To explore the antitumor effect of anthocyanin, a roselle bioactive polyphenol in a rat model of chemical-induced leukemia was assayed. Anthocyanin extract of roselle (Hibiscus anthocyanins, HAs) was supplemented in the diet (0.1 and 0.2%). This study was carried out to evaluate the protective effect of HAs on N-nitrosomethylurea (NMU)-induced leukemia of rats. The study employed male Sprague-Dawley rats (n = 48), and leukemia was induced by intravenous injection of 35 mg kg(-1) body weight of NMU dissolved in physiologic saline solution. The rats were divided into four groups (n = 12): control, NMU only, and HAs groups that received different doses of HAs (0.1 and 0.2%) daily, orally, after NMU injection. After 220 days, the animals were killed, and the following parameters were assessed: morphological observation, hematology examination, histopathological assessment, and biochemical assay. When compared with the NMU-only group, HAs significantly prevented loss of organ weight and ameliorated the impairment of morphology, hematology, and histopathology. Treatment with HAs caused reduction in the levels of AST, ALT, uric acid, and MPO. Also, the results showed that oral administration of HAs (0.2%) remarkably inhibited progression of NMU-induced leukemia by approximately 33.3% in rats. This is the first report to demonstrate that the sequential administration of HAs followed by NMU resulted in an antileukemic activity in vivo.

A review on protocatechuic Acid and its pharmacological potential

Flavonoids and polyphenols are heterocyclic molecules that have been associated with beneficial effects on human health, such as reducing the risk of various diseases like cancer, diabetes, and cardiovascular and brain diseases. Protocatechuic acid (PCA) is a type of widely distributed naturally occurring phenolic acid. PCA has structural similarity with gallic acid, caffeic acid, vanillic acid, and syringic acid which are well-known antioxidant compounds. More than 500 plants contain PCA as active constituents imparting various pharmacological activity and these effects are due to their antioxidant activities, along with other possible mechanisms, such as anti-inflammatory properties and interaction with several enzymes. Over the past two decades, there have been an increasing number of publications on polyphenols and flavonoids, which demonstrate the importance of understanding the chemistry behind the antioxidant activities of both natural and synthesized compounds, considering the benefits from their dietary ingestion as well as pharmacological use. This work aims to review the pharmacological effects of PCA molecules in humans and the structural aspects that contribute to these effects.

Recent advances on the use of biochemical extracts as filaricidal agents

Lymphatic filariasis is a parasitic infection that causes a devastating public health and socioeconomic burden with an estimated infection of over 120 million individuals worldwide. The infection is caused by three closely related nematode parasites, namely, Wuchereria bancrofti, Brugia malayi, and B. timori, which are transmitted to human through mosquitoes of Anopheles, Culex, and Aedes genera. The species have many ecological variants and are diversified in terms of their genetic fingerprint. The rapid spread of the disease and the genetic diversification cause the lymphatic filarial parasites to respond differently to diagnostic and therapeutic interventions. This in turn prompts the current challenge encountered in its management. Furthermore, most of the chemical medications used are characterized by adverse side effects. These complications urgently warrant intense prospecting on bio-chemicals that have potent efficacy against either the filarial worms or thier vector. In lieu of this, we presented a review on recent literature that reported the efficacy of filaricidal biochemicals and those employed as vector control agents. In addition, methods used for biochemical extraction, screening procedures, and structure of the bioactive compounds were also presented.

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes

OBJECTIVES

The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes.

METHODS

Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days.

RESULTS

The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained.

CONCLUSION

The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients.