title: The essential oils chemical compositions and antimicrobial, antioxidant activities and toxicity of three Hyptis species.
abstract: BACKGROUND
  Hyptis suaveolens (Linn.) Poit., Hyptis rhomboidea Mart. et Gal., and Hyptis brevipes Poit., are three species of Hyptis Jacq. (Lamiaceae). Hyptis suaveolens is used for the treatment of fever, headache, gastrointestinal bloating and rheumatism in the traditional folk medicine; Hyptis rhomboidea for hepatitis, ulcer and swollen poison; and Hyptis brevipes for asthma and malaria.
  
  
  OBJECTIVE
  To characterize chemical compositions of the oils from three Hyptis species and evaluate their potential antimicrobial, radical scavenging activities and toxicities against brine shrimp.
  
  
  METHODS
  The oils were obtained by hydrodistillation, and their chemical compositions were investigated by gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentrations (MICs) were determined using the tube double-dilution technique. The antioxidant activities were investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and toxicities by the brine shrimp bioassay.
  
  
  RESULTS
  Forty-seven, 33 and 28 constituents of oils isolated, respectively, from H. suaveolens, H. rhomboidea and H. brevipes were identified. Among the essential oils, the strongest antioxidant activity was exhibited by H. brevipes with an SC₅₀ value of 2.019 ± 0.25 μg mL⁻¹. The H. brevipes oil exhibited the strongest antimicrobial activity (3.125-6.25 μg mL⁻¹) on pathogens employed in the assay. They all showed significant toxicities with median lethal concentration (LC₅₀) values of 62.2 ± 3.07 μg mL⁻¹, 65.9 ± 6.55 μg mL⁻¹ and 60.8 ± 9.04 μg mL⁻¹, respectively.
  
  
  CONCLUSIONS
  The three Hyptis species oils possess strong antimicrobial activities and toxicities. Hyptis rhomboidea and H. brevipes showed considerable antioxidant activity compared to the positive control.
authors.affiliation: The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture and Forestry University, Lin'an, China.
authors.forename: Dian-Hong
authors.initials: DH
authors.lastname: Xu
authors.forename: Ya-Si
authors.initials: YS
authors.lastname: Huang
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Jiang
authors.forename: Ke
authors.initials: K
authors.lastname: Yuan
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects / Q000737:chemistry; D000975:Antioxidants / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*; D001156:Artemia / Q000187:drug effects; D001681:Biological Assay; D002681:China; D004365:Drugs, Chinese Herbal; D020834:Ethnopharmacology; D016166:Free Radical Scavengers / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D008401:Gas Chromatography-Mass Spectrometry; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D031331:Hyptis / Q000737:chemistry*; D020128:Inhibitory Concentration 50; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*; D035261:Plant Components, Aerial / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D016166:Free Radical Scavengers; D009822:Oils, Volatile