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PubMed1998

Antisporulating and respiration-inhibitory effects of essential oils on filamentous fungi.

Sporulation of four species of filamentous fungi, namely Aspergillus fumigatus, Fusarium solani, Penicillium expansum and Rhizopus oryzae, was suppressed by gaseous contact with citron, lavender and thyme oils and, to a lesser extent, by that of perilla and tea tree oils. Lemongrass and cinnamon bark oils were scarcely active. The antisporulating effect of the essential oils was not observed when they were applied as a solution, indicating that their vapours were the active form. Moreover, exposure of fungal cultures to vapours of the active essential oils caused curling of the tips of aerial hyphae (R. oryzae) or incomplete development of conidiophores (A. fumigatus). These antisporulating effects of the vapourizing essential oils seemed to be correlated with their respiration-inhibitory activity, rather than with their growth-inhibitory activity.

Fungi↗
PubMed2000

Comparison of oil recovered from tea tree leaf by ethanol extraction and steam distillation.

Two methods for the determination of oil and oil major components from tea tree (Melaleuca alternifolia) leaf are quantitatively compared. A microwave assisted ethanol extraction and a 2-h hydrodistillation technique were used on both dry and fresh leaf from a low and a high oil concentration tree. There was no significant difference between dry and fresh leaf. The distillation technique recovered 88% and 82% of the extractable oil for the low and high concentration material, respectively. For both samples this distilled oil was composed of lower absolute amounts of sesquiterpenoids and marginally lower amounts of monoterpenoids. Extending the distillation to 6 h increased the sesquiterpenoid recovery but this resulted in a reduction in both the absolute and relative amounts of the oxygenated monoterpenoids, terpinen-4-ol and 1,8-cineole.

Chromatography, Gas↗
PubMed2000

Inhibitory effect of essential oils on apical growth of Aspergillus fumigatus by vapour contact.

The inhibitory effect of seven essential oils on the apical growth of hyphae of Aspergillus fumigatus was studied using a bio cell tracer by vapour contact in a sealed vessel. Based on the inhibitory pattern, these essential oils were classified into three groups. The first group, composed of citron, lavender and tea tree oils, stopped the apical growth in a loading dose of 63 micrograms ml-1 air, but allowed the regrowth of the hyphae after removal of the vapour, indicating fungistatic action. The second group, consisting of perilla and lemon-grass oils, stopped the apical growth in a loading dose of 6.3 micrograms ml-1 air, and did not allow the regrowth after gaseous contact at 63 micrograms ml-1 air, indicative of fungicidal action. The third group, consisting of cinnamon bark and thyme oils, retarded the growth in a dose of 6.3 micrograms ml-1 air, stopped it in a dose of 63 micrograms ml-1 air, and incompletely suppressed regrowth of the hyphae. Gas chromatographic analysis revealed that vapours of essential oils were absorbed on fungal mycelia and agar medium most abundantly by the first group, followed by the second and third groups, reflecting the volatility of the respective groups. Suppression of the apical growth by vapour contact was ascribed to the direct deposition of essential oils on fungal mycelia, together with an indirect effect via the agar medium absorbed.

Aspergillus fumigatus↗
PubMed2003

Toxicity of plant essential oils to Trialeurodes vaporariorum (Homoptera: Aleyrodidae).

A total of 53 plant essential oils were tested for their insecticidal activities against eggs, nymphs, and adults of Trialeurodes vaporariorum Westwood, using an impregnated filter paper bioassays without allowing direct contact. Responses varied according to oil type and dose, and developmental stage of the insect. Bay, caraway seed, clove leaf, lemon eucalyptus, lime dis 5 F, pennyroyal, peppermint, rosewood, spearmint, and tea tree oils were highly effective against T. vaporariorum adults, nymphs, and eggs at 0.0023, 0.0093, and 0.0047 microl/ml air, respectively. These results indicate that the mode of delivery of these essential oils was largely a result of action in the vapor phase. Significant correlations among adulticidal, nymphicidal, and ovicidal activities of the test oils were observed. The essential oils described herein merit further study as potential fumigants for T. vaporariorum control.

Animals↗
PubMed2004

Isolation and partial characterisation of a putative monoterpene synthase from Melaleuca alternifolia.

Melaleuca alternifolia (Cheel) is an Australia native tree harvested for its monoterpene-rich, essential oil. Monoterpene synthases (E.C. 4.2.3.20) were partially purified from the flush growth of the commercially important, high terpinen-4-ol chemotype of M. alternifolia. The purified fractions produced an acyclic monoterpene, linalool that is not present in the essential oil. To further characterise the monoterpene synthase, a cDNA library was constructed and 500 expressed sequence tags (ESTs) were sequenced to isolate putative terpene synthases. A single clone with similarity to the TspB gene sub-family of angiosperm monoterpene and isoprene synthases was isolated but was truncated at the 5' end. This single clone was used to design a probe for a cDNA library and was applied to isolate a full-length clone. This gene encoded a polypeptide 583 amino acids in length (67 kDa) including a putative transit peptide. Heterologous expression of the gene in Escherichia coli and subsequent assay of the recombinant enzyme did not result in the production of terpinen-4-ol, the major constituent of tea tree oil, or of its precursor sabinene hydrate. Significant quantities of linalool were observed in these assays, and in the assays of monoterpene synthase activity of a native enzyme in vitro, but the racemic nature of the linalool means that it may have a non-enzymatic origin.

Base Sequence↗
PubMed2002

An evaluation of selected herbal reference texts and comparison to published reports of adverse herbal events.

OBJECTIVE: There has been a recent proliferation of medical reference texts intended to guide practitioners whose patients use herbal therapies. We systematically assessed six herbal reference texts to evaluate the information they contain on herbal toxicity. METHODS: We selected six major herbal references published from 1996 to 2000 to evaluate the adequacy of their toxicological information in light of published adverse events. To identify herbs most relevant to toxicology, we reviewed herbal-related calls to our regional California Poison Control System, San Francisco division (CPCS-SF) in 1998 and identified the 12 herbs (defined as botanical dietary supplements) most frequently involved in these CPCS-SF referrals. We searched Medline (1966 to 2000) to identify published reports of adverse effects potentially related to these same 12 herbs. We scored each herbal reference text on the basis of information inclusiveness for the target 12 herbs, with a maximal overall score of 3. RESULTS: The herbs, identified on the basis of CPCS-SF call frequency were: St John's wort, ma huang, echinacea, guarana, ginkgo, ginseng, valerian, tea tree oil, goldenseal, arnica, yohimbe and kava kava. The overall herbal reference scores ranged from 2.2 to 0.4 (median 1.1). The Natural Medicines Comprehensive Database received the highest overall score and was the most complete and useful reference source. All of the references, however, lacked sufficient information on management of herbal medicine overdose, and several had incorrect overdose management guidelines that could negatively impact patient care. CONCLUSION: Current herbal reference texts do not contain sufficient information for the assessment and management of adverse health effects of botanical therapies.

Drug Evaluation↗
PubMed2002

[Plant-induced toxic and allergic dermatitis (phytodermatitis)].

Herbal products are being used increasingly for medical or cosmetic purposes. Many cosmetics contain plant extracts for fragrance. Sensitizing plants in cosmetics are tea tree oil, arnica, chamomile, yarrow, citrus extracts, common ivy, aloe, lavender, peppermint, and others. However, the sensitizing potential of these plants varies. Most of the sensitizing substances are sesquiterpene lactones or terpenes. The present paper reviews the various forms of phytodermatitis, including irritant plant dermatitis, phototoxic and photo-allergic dermatitis, allergic dermatitis, and airborne contact dermatitis.

Dermatitis, Allergic Contact↗
PubMed2006

Scabies.

Scabies is a neglected parasitic disease that is a major public health problem in many resource-poor regions. It causes substantial morbidity from secondary infections and post-infective complications such as acute post-streptococcal glomerulonephritis. Disease control requires treatment of the affected individual and all people they have been in contact with, but is often hampered by inappropriate or delayed diagnosis, poor treatment compliance, and improper use of topical compounds such as permethrin, lindane, or benzyl benzoate. In addition to concerns over toxicity with such compounds, parasite resistance seems to be increasing. Oral ivermectin is an alternative that has been used successfully in community control programmes. Plant derivatives such as turmeric, neem, and tea tree oil are also promising future treatments. The disease is strongly associated with poverty and overcrowding, and the associated stigma can ostracise affected individuals. Treatment of scabies in poor countries needs to integrate drug treatment programmes with efforts to improve the socioeconomic conditions and education programmes to reduce stigma. We expect the future to bring more sensitive and specific clinical and laboratory-based diagnostic methods, as well as new therapeutic strategies.

Adult↗
PubMed2003

What's new in burn microbiology? James Laing Memorial Prize Essay 2000.

A variety of factors contribute to the development of infection in burned patients. The role of wound management procedures, risk factors associated with infection, typical bacterial pathogens and associated exotoxins, current problems with antibiotic resistance, wound sampling and rare complications of infection are described. The use of new novel treatments that are currently being developed, such as cell signalling molecules and the increasing use of natural antimicrobial agents, for example honey, papaya fruit and tea-tree oil are discussed. The impact of new methods for earlier detection of infectious agents that could change future practices in burn care is also described.

Aged↗
PubMed2002

Gas chromatography: an investigative tool in multiple allergies to essential oils.

Essential or fragrant oils are volatile odourous mixtures of organic chemical compounds that are widely used in aromatherapy and in the perfume industry. Because of their frequent use, allergy to essential oils is being increasingly recognized. We report 2 cases of multiple allergies to essential oils in professional aromatherapists. Gas chromatography/mass spectrometry was used to analyse the oils in order to identify a common allergen responsible for the contact dermatitis. In both the cases, alpha- and beta-pinene were found to be the most common constituent in the oils and thus appeared to be key allergens. alpha-pinene was confirmed as an allergen on repeat patch testing with pure alpha-pinene in both cases. 12 controls tested were negative for the same. Gas chromatography-mass spectrometry was found to be an extremely useful tool that could be utilized in investigating multiple allergies to essential oils.

Allergens↗
PubMed2002

Development of a paw paw herbal shampoo for the removal of head lice.

The development and clinical testing of an herbal lice removal shampoo, containing a standardized extract of paw paw, thymol, and tea tree oil, are described. All of these ingredients were selected for their ability to deplete adenosine triphosphate (ATP) levels and, thus, prevent ATP-dependent pesticide resistance. Optimum concentrations of the ingredients, treatment times, and dosing schedules were established through in vitro tests with head lice. In addition to pilot studies involving 21 participants, a final clinical trial, using the optimum shampoo formulation in 16 participants, demonstrated 100% effectiveness in removing head lice and nits.

Adult↗
PubMed2003

Herbal medicines for treatment of bacterial infections: a review of controlled clinical trials.

OBJECTIVES: Many hundreds of plant extracts have been tested for in vitro antibacterial activity. This review is a critical evaluation of controlled clinical trials of herbal medicines with antibacterial activity. METHODS: Four electronic databases were searched for controlled clinical trials of antibacterial herbal medicines. Data were extracted and validated in a standardized fashion, according to predefined criteria, by two independent reviewers. RESULTS: Seven clinical trials met our inclusion criteria. Four of these studies were randomized. Three trials of garlic and cinnamon treatments for Helicobacter pylori infections reported no significant effect. Bacterial infections of skin were treated in four trials. Positive results were reported for an ointment containing tea leaf extract in impetigo contagiosa infections. Two trials of tea tree oil preparations used for acne and methicillin-resistant Staphylococcus aureus, and one trial of Ocimum gratissimum oil for acne, reported results equivalent to conventional treatments. CONCLUSIONS: Few controlled clinical trials have been published and most are methodologically weak. The clinical efficacy of none of the herbal medicines has so far been demonstrated beyond doubt. This area seems to merit further study through rigorous clinical trials.

Acne Vulgaris↗
PubMed2005

Pharmacokinetics and pharmacodynamics of injectable testosterone undecanoate in castrated cynomolgus monkeys (Macaca fascicularis) are independent of different oil vehicles.

Testosterone undecanoate (TU) dissolved in soybean oil was developed in China to improve the pharmacokinetics of this testosterone ester in comparison with TU in castor or tea seed oil. As a pre-clinical primate model, three groups of five castrated cynomolgus macaques received either a single intramuscular injection of 10 mg/kg body weight TU in soybean oil, in tea seed oil, or in castor oil (equals 6.3 mg pure T/kg body weight for all preparations). Testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormone as well as prostate volume, body weight and ejaculate weight were evaluated. After injection supraphysiological testosterone levels were induced. There were no significant differences in the pharmacokinetics of the three TU preparations for testosterone and estradiol. The gonadotropin levels showed a high individual variation. Prostate volumes increased equally in all groups after administration and declined to castrate level afterwards. The results suggest that TU in soybean oil produces similar effects as TU in the other vehicles. This study in non-human primates provides no objection to testing of this new preparation in humans.

Animals↗
PubMed2005

The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts to acne-developing organisms.

This study aims to present the in vitro inhibitory effect of Psidium guajava and Juglans regia leaf extracts on the main developer of acne lesions, Propionibacterium acnes (P. acnes), and other organisms that are isolated from acne lesions. Thirty-eight subjects (males and females) who had various types of acne were enrolled in the study. The contents of the acne lesions were cultured and the frequency of P. acnes (alone and with Staphylococci spp.) was 47%, whereas the frequencies for Staphylococcus aureus and Staphylococcus epidermidis were 13% and 24%, respectively. The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts, determined by disk diffusion method (zone of inhibition), were compared to tea tree oil (TTO), doxycycline and clindamycin antibiotics. The zones of inhibition due to the Psidium guajava and Juglans regia leaf extracts ranged from 15.8-17.6 mm against P. acnes, 11.3-15.7 mm against S. aureus and 12.9-15.5 mm against S. epidermidis, respectively. These zones of inhibition were significantly higher than those of TTO and equivalent in case of Staphylococci spp., but less in case of P. acnes, to those obtained from doxycycline or clindamycin. It can be concluded that Psidium guajava and Juglans regia leaf extracts may be beneficial in treating acne especially when they are known to have anti-inflammatory activities.

Acne Vulgaris↗
PubMed2004

Role of antifungal agents in the treatment of seborrheic dermatitis.

Seborrheic dermatitis is a superficial fungal disease of the skin, occurring in areas rich in sebaceous glands. It is thought that an association exists between Malassezia yeasts and seborrheic dermatitis. This may, in part, be due to an abnormal or inflammatory immune response to these yeasts. The azoles represent the largest class of antifungals used in the treatment of this disease to date. In addition to their antifungal properties, some azoles, including bifonazole, itraconazole, and ketoconazole, have demonstrated anti-inflammatory activity, which may be beneficial in alleviating symptoms. Other topical antifungal agents, such as the allylamines (terbinafine), benzylamines (butenafine), hydroxypyridones (ciclopirox), and immunomodulators (pimecrolimus and tacrolimus), have also been effective. In addition, recent studies have revealed that tea tree oil (Melaleuca oil), honey, and cinnamic acid have antifungal activity against Malassezia species, which may be of benefit in the treatment of seborrheic dermatitis. In cases where seborrheic dermatitis is widespread, the use of an oral therapy, such as ketoconazole, itraconazole, and terbinafine, may be preferred. Essentially, antifungal therapy reduces the number of yeasts on the skin, leading to an improvement in seborrheic dermatitis. With a wide availability of preparations, including creams, shampoos, and oral formulations, antifungal agents are safe and effective in the treatment of seborrheic dermatitis.

Administration, Cutaneous↗