**5. Clove**

Clove [*Syzygium aromaticum* (L.) Merr. & L.M. Perry] is one of the most valuable spices of family Myrtaceae and is a native of Indonesia, albeit found all around the globe. Major bioactive component of clove is eugenol. Other components

#### *Spices-Reservoir of Health Benefits DOI: http://dx.doi.org/10.5772/intechopen.96471*

include phenolic acids such as gallic acid, gallic acid derivatives, caffeic acids, salicylic acids; flavonoids such as quercetin, kaempferol (**Figure 4**) [92].

Traditionally used to prevent nausea, enhance blood circulation and liver function, clove is commonly applied for toothache relief and has been long known as a medicine for numerous ailments (**Figure 4**). Miyazawa & Hisama, isolated dehydrodieugenol and trans-coniferyl aldehyde from ethyl acetate extract of clove bud and observed significant activity of both, at a concentration of 0.6 μmol/ mL and 1.2 μmol/ml respectively, against mutagens 4-nitroquinolin 1-oxide and N-methyl-N′-nitro-N-nitrosoguanidine [93]. Furthermore, eugenol and eugenol acetate extracted from aroma extract of clove buds inhibited 99% of hexanal oxidation [94].

Eugenol also exhibits remarkable antimicrobial, antiparasitic, antiviral activities. Essential oil of clove has reportedly inhibited growth of *S. aureus, H. influenzae* (MIC = .0125 ml/ml each), *K. pneumoniae* (MIC = .050 ml/ml) [95], *C. albicans* (MIC = 2.5 μg/ml), *L. monocytogenes* (MIC = 5 μg/ml), *Y. enterocolitica* (MIC = 2.5 μg/ml) [96]. It has been reported that clove decreases ergosterol (cell membrane component) inhibiting growth of *C. albicans* (MIC = 0.64 μg/ml) [97]. Methanol extract, ether soluble fraction (ES), ethyl acetate soluble fraction (EAS) and acetone soluble fraction (AS) of clove buds showed inhibitory effects on *Bacillus cereus* (MIC =250 μg/disc each). Further, EAS and AS also inhibited *Micrococcus luteus* and *Shigella dysenteriae* respectively (MIC = 62.5 μg/disc each) [98]. In addition, antiparasitic effects were reported by Bagavan et al., who observed growth inhibition of chloroquine resistant *P. falciparum* on treatment with ethyl acetate and methanol extracts of clove (IC50 = 13 μg/ml and 6.25 μg/ml

**Figure 4.** *Chemical constituents and biological properties of Clove.*

respectively) [99]. Hypoglycemic effects of clove have also been identified. Methanol extract of clove activated AMP-activated protein kinase (AMPK) pathway, a regulator of cellular energy homeostasis thereby regulating glucose metabolism [100]. A recent report has pointed out that it relieves insulin resistance [101].

Consumption of clove is safe, and it offers numerous benefits, however, studies have shown that clove oil increases clotting time [102] which might increases the risk of bleeding in case of bleeding disorders.
