title: Phytosynergy in some Hypoxis species and pharmacological properties of a Hypoxis-based phytopharmaceutical formula.
abstract: BACKGROUND
  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).
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3201, South Africa.
authors.forename: A R
authors.initials: AR
authors.lastname: Ndhlala
authors.forename: G I
authors.initials: GI
authors.lastname: Stafford
authors.forename: J
authors.initials: J
authors.lastname: Van Staden
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D051545:Cyclooxygenase 1 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D027802:Hypoxis; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D002800:Cholinesterase Inhibitors; D016861:Cyclooxygenase Inhibitors; D010936:Plant Extracts; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D000110:Acetylcholinesterase
keywords: 70% aqueous ethanol; AChE; AIDS; APE; ATCC; African potato; African potato extract (Ngwenya quality products); American type culture collection; B.s.; Bacillus subtilis; COX; CYP450; Cyclooxygenase (COX); E.c.; Escherichia coli; EtOH; FIC; HA; HC; HH; HIV; HR; HepG2; Herbal preparation; Hypoxis acuminate; Hypoxis colchicifolia; Hypoxis hemerocallidea; Hypoxis rigidula; Isobologram studies; K.p.; Klebsiella pneumonia; MFC; MIC; NFκB; Phytopharmaceutical formula; R(f); S.a.; Staphylococcus aureus; Syn; Synergism; TLC; UV; acetylcholinesterase; acquired immunodeficiency syndrome; cyclooxygenase; cytochrome P450; fractional inhibitory concentration; human hepatocellular liver carcinoma; human immunodeficiency virus; minimum fatal concentration; minimum inhibitory concentration; nuclear factor κB; retardation factor; synonym; thin layer chromatographic; ultraviolet