A capillary zone electrophoresis method for the quantitative determination of hypoxoside in commercial formulations of African potato (Hypoxis hemerocallidea)

Norlignan glucosides from Hypoxis hemerocallidea and their potential in vitro anti-inflammatory activity via inhibition of iNOS and NF-κB

Eleven diarylpentanoid/norlignan glucosides, along with five other specialized metabolites, were isolated and characterized from the hydro-alcoholic extract of Hypoxis hemerocallidea corms. Hypoxhemerolosides A-F were found to be undescribed compounds. Curcapicycloside was isolated and identified for the first time in its original form, previously it was reported as a methylated derivative. In addition, (1S,2R)-1-(3,4-dihydroxyphenyl)-5-(4-β-D-glucopyranoxy-3-hydroxyphenyl)-1-methoxypent-4-yn-2-ol and (1S,2R)-1-(3,4-dihydroxyphenyl)-1-ethoxy-5-(4-β-D-glucopyranoxy-3-hydroxyphenyl)pent-4-yn-2-ol were isolated and characterized as artifacts, generated during extraction/isolation procedures from possible 1-(3,4-dihydroxyphenyl)-5-(4-β-D-glucopyranoxy-3-hydroxyphenyl)pent-4-yne-1,2-diol. Structure elucidation was mainly achieved by the interpretation of 1D and 2D NMR and HRESIMS data. The isolated compounds were screened for anti-inflammatory activity in terms of iNOS and NF-κB inhibition as well as for cytotoxicity. Hypoxhemerolosides C-E and obtuside A moderately inhibited nitric oxide production in LPS-stimulated mouse macrophages (RAW 264.7).

In Vitro Investigation of Potential Anti-Diabetic Activity of the Corm Extract of Hypoxis Argentea Harv. Ex Baker

The corms of Hypoxis argentea are widely used as a traditional remedy for diabetes mellitus in South Africa. In this study, we investigated the effects of non-toxic concentrations (12.5-100 μg mL-1) of the aqueous extract of H. argentea (HAA) corms on glucose uptake, pancreatic beta cell proliferation, and adipocyte differentiation. HAA stimulated glucose uptake in HepG2 cells up to 19.6 % and 17.0 % in L6 myotubes. Live-cell imaging microscopy revealed significant increases (p < 0.001) in total INS-1 cell numbers exposed to HAA, although no effect was observed on adipogenesis in 3T3-L1 pre-adipocytes. HAA produced weak to moderate inhibition of porcine pancreatic α-amylase, α-glucosidase, porcine pancreatic lipase, dipeptidyl peptidase IV (DPP IV) activities, as well as protein glycation. Our results suggest that the acclaimed anti-diabetic effects of H. argentea could be mediated by its promotion of glucose utilization and preservation of pancreatic beta cell populations while preventing fat accumulation in adipocytes.

Hypoxis (Hypoxidaceae) in African traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Hypoxis species (Hypoxidaceae) are popular medicinal plants used in the African traditional medicine to treat numerous ailments and are reported to have a wide spectrum of pharmacological properties. In this paper we reviewed and evaluated the traditional uses, pharmacological, phytochemistry and toxicity aspects of the genus Hypoxis. Potential medicinal prospects and possible knowledge gaps and pitfalls are discussed.

MATERIALS AND METHODS

A comprehensive and systematic review of literature on Hypoxis species was done using numerous resources such as books and scientific databases that include Pubmed, Scopus, Scirus, Google scholar, Web of Science and others. Information on the various pharmacological and chemical properties of Hypoxis extracts was critically analysed and discussed under the various topics.

RESULTS

The literature indicated a broad range of uses, pharmacological and toxicological properties of different Hypoxis species extracts and their relevance to African healthcare systems. Several compounds, mostly glucosides, sterols and sterolins, have been isolated, identified and tested in various in vitro and in vivo models as well as in a couple of clinical trials with a lot of promising prospects reported in some studies.

CONCLUSION

A critical analysis of the available literature and studies identifies positive potential for the future use of Hypoxis species in both traditional and modern medicine and concurrently so with possible pitfalls and research gaps in current knowledge. An integrated and holistic approach to addressing research issues, particularly toxicology aspects could be more effectively applied and incorporate conservation strategies for the species.

Phytosynergy in some Hypoxis species and pharmacological properties of a Hypoxis-based phytopharmaceutical formula

ETHNOPHARMACOLOGY RELEVANCE

Hypoxis species are used extensively in traditional medicine in southern Africa for several ailments including tuberculosis, chest infections, and nervous and urinary disorders. Several other claims have been made for extracts emanating from Hypoxis species and have led to the production of several commercial products used as immunostimulants mostly for people living with HIV/AIDS and cancer. This study was aimed at investigating the biological activity of four Hypoxis species and a commercial herbal product, 'African potato extract' (APE).

MATERIALS AND METHODS

Antibacterial, antifungal, cyclooxygenase (COX) and acetylcholineasterase (AChE) inhibitory activities of four Hypoxis species (H. acuminata, H. colchicifolia, H. hemerocallidea and H. rigidula) and a popular Hypoxis-based herbal preparation, APE were tested. The phytoconstituents of the mixture were also profiled using TLC methods. Several combinations of the Hypoxis species were prepared and their synergism, additive, autonomic and antagonism effects investigated. As a quality control measure, batch to batch comparison in the phytoconstituents and biological activity of APE was carried out.

RESULTS

The results confirmed H. colchicifolia and H. hemerocallidea as the phytoconstituents of APE. The extracts showed a broad spectrum of activities against the bacterial and fungal strains used. Of particular interest were the activities exhibited by the APE and combinations of H. colchicifolia and H. hemerocallidea. The APE mixture exhibited good antibacterial activity (MIC values of 0.78mg/ml each) in all the tested batches against the bacterial strains used. The water extracts of all four Hypoxis species, three batches of APE and the combination (water extracts) of H. colchicifolia and H. hemerocallidea exhibited high COX-1 and moderate COX-2 inhibitory activity except for H. acuminata which showed low activity against COX-2. All the extract, batches of APE and combinations showed low to moderate AChE inhibitory activity. These results provided some evidence of phytosynergy in some extracts of H. hemerocallidea and H. colchicifolia except for a few extracts which act as additive, autonomous and antagonistic when used to inhibit some bacterial and fungal strains. However, this was not the case for COX and AChE inhibition, as only acetone extracts acted in a synergistic way to reduce the activity of the enzyme.

CONCLUSION

Even though the results give an indication of a positive interaction between some extracts of H. hemerocallidea and H. colchicifolia, the study was carried out on 1:1 v/v combinations only. It is therefore important to carry out isobologram studies, which considers more than one ratio of the combinations.

Prophylactic treatment with Hypoxis hemerocallidea corm (African potato) methanolic extract ameliorates Brachyspira hyodysenteriae-induced murine typhlocolitis

Brachyspira hyodysenteriae is the causative agent of swine dysentery and induces a characteristic mucosal inflammation resulting in pronounced typhlocolitis in swine and mice. Hypoxis hemerocallidea corm (African potato) is a traditional medicine in southern Africa. An African potato methanolic extract (APME) and one of its major constituents, hypoxoside, have been shown in vitro to possess an anti-inflammatory property. The aim of this study is to evaluate the ability of APME to prevent or ameliorate B. hyodysenteriae-induced typhlocolitis. Mice were orally treated with APME for seven days prior to B. hyodysenteriae infection and the treatments continued daily for seven days postinfection (DPI). At the termination of the experiment, weight loss, gross and histological lesions, myeloperoxidase (MPO) activity, and intestinal epithelial proliferation were evaluated. In addition, the protein level of activated p65 subunit of nuclear factor- κB (NF- κB) and mRNA expression of NF- κB-associated genes were also measured. APME treatment significantly ( P < 0.05) reduced weight loss, the severity of typhlocolitis, mucosal MPO activity and intestinal epithelial proliferation subsequent to B. hyodysenteriae infection. Mucosal protein levels of active p65 and expression levels of NF- κB-associated genes following B. hyodysenteriae infection were also decreased by the oral treatment with APME. In conclusion, prophylactic treatment with APME ameliorated B. hyodysenteriae-induced typhlocolitis, suggesting H. hemerocallidea corm methanolic extract may have potential for ameliorating enteropathies that are mediated by overactive host inflammatory processes.

Hypoxis hemerocallidea--not merely a cure for benign prostate hyperplasia

The use of Hypoxis hemerocallidea Fisch. and C.A. Mey. (Hypoxidaceae) extracts for ailments other than benign prostate hyperplasia (BPH) is now a reality. The whole extract, the phytosterols, as well as the major constituents it contains (hypoxoside, and its active derivative rooperol) are now finding new applications in the area of anti-oxidants, anti-inflammatories, anti-diabetics, anti-convulsants, inhibitors of drug marker substances and new evidence is presented of activity against cancerous and premalignant cancer cells. In addition, the over-the-counter (OTC) trade has undergone enormous expansion.