Efficacy of garlic (Allium sativum) extract applied as a therapeutic immersion treatment for Neobenedenia sp. management in aquaculture

Garlic, Allium sativum L., extract administered as a therapeutic bath was shown to have antiparasitic properties towards Neobenedenia sp. (MacCallum) (Platyhelminthes: Monogenea) infecting farmed barramundi, Lates calcarifer (Bloch). The effect of garlic extract (active component allicin) immersion on Neobenedenia sp. egg development, hatching success, oncomiracidia (larvae) longevity, infection success and juvenile Neobenedenia survival was examined and compared with freshwater and formalin immersion. Garlic extract was found to significantly impede hatching success (5% ± 5%) and oncomiracidia longevity (<2 h) at allicin concentrations of 15.2 μL L(-1) , while eggs in the seawater control had >95% hatching success and mean oncomiracidia longevity of 37 ± 3 h. At much lower allicin concentrations (0.76 and 1.52 μL L(-1)), garlic extract also significantly reduced Neobenedenia infection success of L. calcarifer to 25% ± 4% and 11% ± 4%, respectively, compared with 55% ± 7% in the seawater control. Juvenile Neobenedenia attached to host fish proved to be highly resistant to allicin with 96% surviving 1-h immersion in 10 mL L(-1) (15.2 μL L(-1) allicin) of garlic extract. Allicin-containing garlic extracts show potential for development as a therapy to manage monogenean infections in intensive aquaculture with the greatest impact at the egg and larval stages.

Antimycobacterial and Antibacterial Activity of Allium sativum Bulbs

Tuberculosis is one of the major public health problems faced globally. Resistance of Mycobacterium tuberculosis to antitubercular agents has called for an urgent need to investigate newer drugs to combat tuberculosis. Garlic (Allium sativum) is an edible plant which has generated a lot of curiosity throughout human history as a medicinal plant. Garlic contains sulfur compounds like allicin, ajoene, allylmethyltrisulfide, diallyltrisulfide, diallyldisulphide and others which exhibit various biological properties like antimicrobial, anticancer, antioxidant, immunomodulatory, antiinflammatory, hypoglycemic, and cardiovascular effects. According to various traditional systems of medicine, garlic is one of the established remedies for tuberculosis. The objective of the current study was to investigate in vitro antimycobacterial activity as well as anti-bacterial activity of various extracts rich in specific phytoconstituents from garlic. Preparation of garlic extracts was done based on the chemistry of the constituents and their stability. The estimation of in vitro antimycobacterial activity of different garlic extracts was done using Resazurin microtire plate assay technique whereas activity of garlic oil was evaluated by colony count method. The antibacterial activity of extracts and oil was estimated by zone of inhibition method. Extracts of garlic rich in allicin and ajoene showed appreciable antimycobacterial activity as compared to standard drugs. Garlic oil demonstrated significant antibacterial activity, particularly against methicillin-resistant Staphylococcus aureus.

Anti-oncogenic perspectives of spices/herbs: A comprehensive review

Contemporary nutrition regime has focused the attention of the researchers on phytochemicals enriched spices to mitigate various oncological threats. Numerous chemopreventive strategies against malignancy have been developed considering the anticancer perspectives of allied nutraceutical constituents. Current evidences have proven an inverse association of spices with that of oncological incidences. The high antioxidant activity of spices derived bioactives triggers the free radicals scavenging ability at cellular level thereby alleviating various metabolic syndromes. Promising compounds including curcumin and curcuminoids (turmeric), limonene (cardamom), allicin, allyl isothiocyanate (garlic), cinnamic aldehyde, 2-hydroxycinnamaldehyde and eugenol (cinnamon), gingerol, zingiberone, zingiberene (ginger), dipropyle disulfides and quercetin (onion), piperidine piperine, limonene, α- and β-pinene (black pepper), crocetin, crocin and safranal (saffron) have been identified as chemopreventing agents against various malignancies. Chemopreventive properties of spices are mediated by functional bioactive ingredients that arrest the activity of cytochrome P450 and isozymes CYP 1A1, cyclooxygenase-2, reducing activator of transcription-3 (STAT-3) and signal transducer. They are closely associated with tumorigenesis activated by interleukin-6 (IL-6) receptors and epidermal growth factor (EGF) relate to an array of tumors. The bioactive constituents altering the expression of protein involved in cell cycle, activating caspases killer and suppressing Kappa-B activation. Alongside, they also restrain causative agents of cell structure damage as in lipid and protein membrane system and DNA that shifting healthy body towards cancerous state. Spices phytochemicals have established as carcinogenesis blockers by modulating cell proliferation pathways transformation, inflammation, metastasis etc. Furthermore, spices as functional ingredients may act as immune boosters and diminish inflammatory disorders. The current review is inevitably an affirmative approach in the development of novel guidelines against cancer by using dietary species to maintain good health.

Trifluoperazine and CEF-allicin from garlic (Allium sativum) as potential new antitubercular drugs active against drug resistantMycobacterium tuberculosis

Trifluoperazine (TFP) and a compound called CEF-allicin purified from garlic (Allium sativum) possess antitubercular activity against both drug susceptible and resistant clinical isolates ofMycobacterium tuberculosis. They are bactericidal in nature with multiple sites of primary action. This new use for known drug TFP was based on our observation that mycobacteria have calmodulin like protein which regulates their metabolism and a calmodulin antagonist has antitubercular activity. The minimum inhibitory concentration (MIC) of TFP againstM. tuberculosis was 4-5 μg/ml. It inhibited considerably by 6hrs, the synthesis of total lipids from(14)C-acetate and proteins and DNA as judged by the uptake of(14)C-glycine and(3)H-thymidine respectively by the bacilli. With 50 clinical isolates from our hospital at Delhi, the MIC was 4μg/ml, for 40% and 8μg/ml, for 50% of the isolates susceptible as well as resistant to one or more of the five drugs isoniazid, rifampicin, streptomycin, ethambutol and pyrazinamide. The MIC of CEF-allicin was 25μg/ml, for bothMycobacterium tuberculosis and isoniazid resistant clinical isolate TRC-C 1193. It inhibited in 6hrs or less the synthesis of total lipids completely and proteins and DNA ofM. tuberculosis from its labeled precursors almost completely.

Allicin modulates the antioxidation and detoxification capabilities of primary rat hepatocytes

The effect of allicin, an active ingredient of garlic, on lactate dehydrogenase (LDH) leakage, lipid peroxidation, glutathione (GSH) content, and GSH-related enzyme activity was investigated in primary hepatocytes. In this study, allicin was synthesized in our laboratory as an experimental material, and primary hepatocytes isolated from Sprague-Dawley rats were used as an experimental model. According to the results, hepatocytes treated with 10 μM allicin did not differ from the control on LDH leakage during various incubation times. When the hepatocytes were treated with 10 μM allicin, their levels of thiobarbituric acid reactive-substances (TBARS) did not differ significantly from that of the control within the 8-h incubation. However, the TBARS values of hepatocytes treated with 30 and 50 μM allicin were higher compared to the control after incubation for 4 h and 8 h, respectively. The hepatocyte intracellular GSH content was significantly higher than that of the control after 30 μM allicin treatment, but treatment with 50 μM allicin caused a significant GSH depletion after incubation for 4 h or longer. In addition, when hepatocytes were treated for 24 h with 10 or 30 μM allicin, glutathione peroxidase (GPx) activity was significantly increased compared to that of the control, whereas 50 μM allicin treatment for 24 h or longer significantly decreased the GPx activity. Glutathione reductase (GRd) activity was significantly increased when the hepatocytes were treated with 10 μM allicin for 24 h, but GRd activity significantly decreased when the hepatocytes were treated with 50 μM allicin. However, hepatocytes treated for 24 h with 10 or 30 μM allicin showed significantly increased glutathione S-transferase (GST) activity compared to the control. These results suggest that 10 μM allicin potentially enhances the antioxidation and detoxification capabilities of primary rat hepatocytes.

Enhancing effects on vacuole-targeting fungicidal activity of amphotericin B

Invasive fungal infections are major threats for immunocompromised patients as well as for those undergoing cancer chemotherapy. Amphotericin B (AmB), a classical antifungal drug with a polyene macrolide structure, is widely used for the control of serious fungal infections. However, the clinical use of this antifungal drug is limited by its side effects and the emergence of drug-resistant strains. AmB lethality has been generally attributed to alterations in plasma membrane ion permeability due to its specific binding to plasma membrane ergosterol. Recent studies with Saccharomyces cerevisiae and Candida albicans reveal the vacuole disruptive action as another cause of AmB lethality on the basis of marked amplification of its activity in combination with allicin, an allyl-sulfur compound from garlic. The enhancing effect of allicin is dependent on the inhibition of ergosterol-trafficking from the plasma membrane to the vacuole membrane, which is considered to be a cellular response to protect against disintegration of the vacuole membrane. The polyol macrolide niphimycin (NM) also possesses vacuole-targeting fungicidal activity, which is greater than that of AmB and nystatin. The alkyl side chain attached to the macrolide ring of NM is considered to possess an allicin-like inhibitory effect on the intracellular trafficking of ergosterol. The vacuole-targeting fungicidal activity was additionally detected with a bactericidal cyclic peptide polymyxin B (PMB), and was markedly enhanced when administered together with allicin, monensin, or salinomycin. The synergistic fungicidal activities of AmB and allicin may have significant implications for the development of vacuole-targeting chemotherapy against fungal infections.

Allicin reduces the production of α-toxin by Staphylococcus aureus

Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin, an organosulfur compound, was active against S. aureus with MICs ranged from 32 to 64 μg/mL. Haemolysis, Western blot and real-time RT-PCR assays were used to evaluate the effects of allicin on S. aureus α-toxin production and on the levels of gene expression, respectively. The results of our study indicated that sub-inhibitory concentrations of allicin decreased the production of α-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in a dose-dependent manner. Furthermore, the transcriptional levels of agr (accessory gene regulator) in S. aureus were inhibited by allicin. Therefore, allicin may be useful in the treatment of α-toxin-producing S. aureus infections.

Composition, stability, and bioavailability of garlic products used in a clinical trial

In support of a new clinical trial designed to compare the effects of crushed fresh garlic and two types of garlic supplement tablets (enteric-coated dried fresh garlic and dried aged garlic extract) on serum lipids, the three garlic products have been characterized for (a) composition (14 sulfur and 2 non-sulfur compounds), (b) stability of suspected active compounds, and (c) availability of allyl thiosulfinates (mainly allicin) under both simulated gastrointestinal (tablet dissolution) conditions and in vivo. The allyl thiosulfinates of blended fresh garlic were stable for at least 2 years when stored at -80 degrees C. The dissolution release of thiosulfinates from the enteric-coated garlic tablets was found to be >95%. The bioavailability of allyl thiosulfinates from these tablets, measured as breath allyl methyl sulfide, was found to be complete and equivalent to that of crushed fresh garlic. S-Allylcysteine was stable for 12 months at ambient temperature. The stability of the suspected active compounds under the conditions of the study and the bioavailability of allyl thiosulfinates from the dried garlic supplement have validated the use of these preparations for comparison in a clinical trial.