Here is an essay on ‘Cloves’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Cloves’ especially written for school and college students.
Essay on Cloves
1. Essay on Cloves (As an Antimicrobial Foods):
The antimicrobial activity of clove is attributable to eugenol, oleic acids and lipids found in its essential oils. The biological activity of Eugenia caryophyllata has been investigated on several pathogenic and spoilage microorganisms and parasites, Herpes simplex and hepatitis C viruses and also the antimicrobial activity against a large number of multi-resistant Staphylococcus species isolated from dialysis biomaterials.
Cloves displayed an important antifungal effect against the tested 53 human pathogenic yeasts using a disc paper diffusion method. It is clear that clove oil shows powerful anti-fungal activity. The essential oil of cloves and Eugenol showed inhibitory activity against all the tested Candida, and Aspergillus. Clove oil and eugenol also caused a considerable reduction in the quantity of ergo sterol, a specific fungal cell membrane component.
Nzeako et al (2006) showed that the place of cultivation has no effect on clove’s antimicrobial activity as there was no significant difference in antimicrobial activity between cloves obtained from Sri Lanka or Zanzibar or thyme obtained from Iran or Oman.
Clove essential oil and eugenol, the antifungal constituent of clove oil presented prominent anti-fungal action with MIC of 1 per cent and 4 per cent, respectively on fungal strains isolated from onychomycosis. Eugenol was the most effective antifungal agent against the dermatophytes T. mentagrophytes and M. canis, T. rubrum, E. floccosum, and M. gypseum.
The activities of clove oil against the dermatophytes tested were highest at a concentration of 0.2 mg/ml, with an effectiveness of more than 60 per cent hyphal growth completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum.
Germ tube formation by Candida albicans was almost completely inhibited by clove oil and eugenol concentrations below the MIC values. Presence of anti-quorum sensing (QS) activity in clove oil and other essential oils has indicated new anti-infective activity. The identification of anti-QS phyto-constituents is needed to assess the mechanism of action against both C. violacenm and P. aeruginosa. Because of its anti-QS activity, clove bud essential oil might be important in reducing virulence and pathogenicity of drug-resistant bacteria in vivo.
The anti-bacterial activity of the clove oil and its major compounds, eugenol and β-caryophyllene were compared, the same was higher for clove oil than β- caryophyllene but was similar to eugenol against all tested oral bacteria suggesting that the clove oil and eugenol could be employed as a natural anti-bacterial agent against cariogenic and periodontopathogenic bacteria.
The antimicrobial activity of combinations of the two essential oils from clove and rosemary indicated their additive, synergistic or antagonistic effects against individual micro-organisms. The time-kill curves of clove and rosemary essential oils towards Staphylococcus epidermidis, Escherichia coli and Candida albicans showed clearly the bactericidal and fungicidal processes. Cinnamon oil and clove oil strongly inhibited the growth of E. coli O157:H7 at neutral and acidic pH. A synergistic effect between the essential oils and the lower pH of the growth medium was evident by consistently lower MICs at pH 4.5.
The addition of either essential oil (cinnamon and clove oils at 0.01 per cent vol/vol) resulted in lower D-values of E. coli O157:H7 than those for cider alone, suggesting a synergistic effect and the potential efficacy of a mild heat treatment for apple cider.
Mixtures of cinnamon and clove oils were tested for inhibitory activity against important spoilage micro-organisms of intermediate moisture foods. Aspergillus flavus and Eurotium sp. proved to be the most resistant micro-organisms out of four fungal species (A. flavus, P. roqueforti, M. plumbeus and Eurotium sp.). Cinnamon and clove oil added between 1000 and 4000 microL at a ratio of 1:1 were tested for minimum inhibitory volume (MIV) against molds and four yeasts species (D. hansenii, P. membranaefaciens, Z. rouxii and C. lipolytica).
The gas phase above 1000 microL of the oil mixture inhibited growth of C. lipolytica and P. membranaefaciens; 2000 micro L inhibited growth of A. flavus, P. roqueforti, M. plumbeus, Eurotium sp., D. hansenii, and Z. rouxii, while inhibition of A. flavus required the addition of 4000 microL. Higher ratios of cinnamon oil/clove oil were more effective for inhibiting the growth of A. flavus.
Oregano and clove oils have been shown to possess a broad spectrum of antimicrobial activity. Chami et al. (2005) observed these two essential oils to effect yeast cell lysis by the release of substances absorbing at 260 nm. In addition, scanning electron microscopy analyses revealed that the surface of treated cells by oregano and clove oils was significantly damaged.
Eugenol from clove inactivated S. typhi within 60 min exposure. The chemo- attractant property of eugenol combined with the observed high anti-bacterial activity at alkaline pH favors the fact that the compound can work more efficiently when given in vivo. Eugenol increased the permeability of the membrane and thus Devi et al. (2010) confirmed the disruptive action of eugenol on cytoplasmic membrane.
The antimicrobial activities of allspice, cinnamon, and clove bud oils in apple puree film-forming solutions formulated into edible films at 0.5 per cent to 3 per cent (w/w) concentrations showed higher influence against L. monocytogenes than against the S. enterica. The antimicrobial activities against the 3 pathogens, E. coli O157:H7, S. enterica, and L. monocytogenes were in the following order – cinnamon oil > clove bud oil > allspice oil.
Rattanachaikunsopon and Phumkhachorn (2009) indicated that clove oil has a higher protective effect on experimental L. garvieae infection in tilapia and better potential to replace antibiotics for controlling the disease when compared to cinnamon, ginger and holy basil oils.
C. albicans was found to be the most susceptible organism to the influence of thyme and clove oil with concentration end-points of 0.1 per cent (1024) and 0.2 per cent (512) respectively. Clove water extract showed inhibitions with all the organisms tested except with S. pyogenes, B. fragilis and C. albicans.
An extract from the flower buds of E. caryophyllus (Spreng.) and the essential oil, eugenol, were evaluated by Tragoolpua and Jatisatienr (2007) for their anti-Herpes simplex virus properties on standard HSV-1(F), standard HSV-2(G) and ten HSV isolates. The plaque reduction assay showed that HSV-1(F), HSV-2(G), two HSV-1 isolates (2, 30) and four HSV-2 isolates (1, 2, 3, 21) were inhibited by E. caryophyllus.
Only HSV-1 isolates 1 and 30 were inhibited by eugenol. The anti-HSV activity of eugenol against HSV-1 (F) and HSV isolates was stronger than with the E. caryophyllus crude extract. However, the percentage inhibition was more pronounced on HSV- 1(F) than on HSV-2(G). Moreover, HSV-1(1) and HSV-2(1, 32) could not replicate when eugenol was included in the assay.
Essential oils of clove, basil and the oil constituents (eugenol and linalool) inhibited parasite growth, with clove essential being the most effective one. Ultra structural alterations were observed mainly in the nucleus. Essential oil of clove, dispersed (0.4 per cent v/v) in a concentrated sugar solution, had a marked germicidal effect against various bacteria e.g. C. albicans. S. aureus (five strains), K. pneumoniae, P. aeruginosa, C. perfringens, E. coli and C. albicans inoculated in laboratory broth supplemented with 63 per cent (v/w) of sugar, and containing 0.4 per cent (v/w) of essential oil of clove were killed. The concentrated sugar solution provided a good vehicle for obtaining an oil dispersion that is relatively stable for certain practical applications.
Clove oil was found to possess strong antifungal activity against opportunistic fungal pathogens such as C. albicans, C. neoformans, A. fumigatus, etc. The oil was found to be extremely successful in the treatment of experimental murine vaginitis in model animals. On evaluating various formulations, topical administration of the liposomized clove oil was found to be most effective against treatment of vaginal candidiasis.
Role in Food Preservation:
Mycelial growth of the four test pathogens namely P. vagabunda, P. expansum, B. cinerea and M. fructigena was completely inhibited when treated with 150 microl 1(- 1) of volatile eugenol whether at 4 or 20° C. Ethoxylate- and Tween 80-eugenol formulations applied at room temperature were ineffective in reducing disease incidence. When heated to 50° C, both formulations induced phytotoxicity on apple surface and caused cuticle damages as revealed by scanning electronic microscopic observations. The application of heated lecithin-formulated eugenol could become a successful alternative to the traditional fungicides used in postharvest disease management of apple fruit.
Cava et al. (2007) indicated the possibility of using three essential oils (EOs) i.e., the oil of the cinnamon bark, clove and cinnamon leaf in milk beverages as natural antimicrobials, especially because milk beverages flavored with cinnamon and clove are consumed worldwide and have been receiving high popularity in recent years.
A crude methonolic extract of clove exhibited preferential growth-inhibitory activity against Gram-negative anaerobic periodontal oral pathogens, including P. gingivalis and P. intermedia. Also the flavones, kaempferol and myricetin, isolated from cloves showed potent growth-inhibitory activity against the periodontal pathogens P. gingivalis and P. intermedia.
Clove oil was found to be fungistatic and fungicidal against L. theobromae, C. musae and F. proliferatum, (responsible for crown rot in banana) and anthracnose and crown rot pathogens within a range of 0.03-0.11 per cent (v/v). It was therefore suggested that clove essential oil could be used as an alternative post-harvest treatments which is chemically safe and acceptable to consumers whereas Benomyl (Benlate), which is currently used to manage fungal pathogens in banana, can cause adverse health effects.
But no antimicrobial effect of 1 per cent (w/w) clove powder on L. monocytogenes was observed in cheese after 1 or 2 weeks either at lower or higher temperature. Hence, the antimicrobial effect of cloves could be organism specific.
2. Essay on Cloves (As an Anti-Obesity Foods):
In vitro investigation of the effect of ethanol extract of cloves on 3T3-L1 cells revealed that it had efficiently inhibited the conversion of cells into adipocytes in a dose-dependent manner. In vivo investigation revealed that supplementation with ethanol extract of cloves had significantly decreased HFD-induced increases in the body weight, liver weight, white adipose tissue (WAT) mass, and serum TG, TC, lipid, glucose, insulin and leptin levels.
Consistent with its effects on liver weight and WAT mass, SAE supplementation was found to have suppressed the expression of lipid metabolism-related proteins, including SREBP-1, FAS, CD36 and PPARγ in the liver and WAT, in addition to down regulating mRNA levels of transcription factors including Srebp and Pparg. SAE inhibits fat accumulation in high fat diet-fed mice via the suppression of transcription factors integral to adiposeness and lipogenesis, suggesting its potential in preventing obesity.