**6.3 Anticancer activity**

*Phytochemicals in Human Health*

proton motive force [91–93].

**Figure 3.**

*Types of antioxidants.*

8 microorganisms tested by Carovic-Stanko et al. [102].

mate, α-cubebene, caryophyllene, β-ocimene and α-farnesene.

clarified, although various modes of action in the bacterial cell have been discussed including degradation of the cell wall, damage to cytoplasmic membrane and membrane proteins, leakage of cell contents, coagulation of cytoplasm, and depletion of

The antibacterial and antifungal activities of *Ocimum* species have been studied on various bacteria and fungi [29, 94–96]. These studies indicate that essential oils are more efficient antifungals and antibacterials compared to the polar extracts [97–99]. *Ocimum sanctum* essential oils showed remarkable antimicrobial activity against bacteria and other microorganisms, such as periodontopathogens [100], mainly due to the presence of oxygenated monoterpenes in their chemical compositions [101]. The essential oil and methanol extracts of five *Ocimum* species have an appreciable activity against seven human pathogenic bacteria [29], essential oils of *Ocimum* species showed strong antimicrobial activity against all seven microorganisms tested. Oils of seven *Ocimum* taxa (*O. americanum* L., *O. basilicum* L., *O. campechianum* Mill., *O.* x *citriodorum* Vis., *O. kilimandscharicum* Baker ex Gürke and three botanical varieties and cultivars of *Ocimum basilicum* L.: 'Genovese', var. difforme and var. purpurascens)) showed strong antimicrobial activity against all

Among the antifungal activities, the *in vitro* antifungal activity of *O. basilicum* L. essential oil against Aspergillus flavus fungal growth and aflatoxin B1 production [103], essential oils of *O. basilicum* L. showed strong antifungal activity against *A. flavus*, and the main components were linalool, 1,8-cineol, eugenol, methyl cinna-

**190**

For a long time, the polyphenols of the *Ocimum* oil of the diet have been considered to play a role for the prevention of certain types of cancer in the Asian origin [104]. Even more than in *Ocimum* oil, constituents present in *Ocimum* leaf extract has shown strong antioxidant potency and inhibition of cancer cell proliferation, thus suggesting the protection against the genotoxic action of the ROS as one of the mechanisms explaining the anticancer effects of these compounds. Indeed, either methanol aqueous *Ocimum basilicum* L. leaf extract or the isolated constituents eugenol epoxide free radical scavenging activity and growth inhibition at low micromolar concentration on human breast cancer cell lines (MCF-7 and MDA-MB-231) [105, 106] and Human cancerous cell lines (HL60 promyelocytic blood leukemia cells) [107]. Such findings were further confirmed by other in vitro reports, testing the effects of *Ocimum basilicum* L. against four different humans cancer cell lines viz. human cervix adenocarcinoma HeLa cells, human melanoma FemX cells, human chronic myelogenous leukemia K562 cells, and human ovarian SKOV3 cells [108]. Furthermore, Karthikeyan et al. [109] demonstrated regression of tumors caused by orally administrated aqueous and ethanolic extracts of *Ocimum sanctum* in mice that developed spontaneous soft tissue sarcomas.

Monga et al. [110] studied the antimelanoma and radioprotective activity of essential oils obtained by 50% alcoholic aqueous leaf extract from five species of *Ocimum* viz. *Ocimum sanctum* (SE), *Ocimum gratissimum*, *Ocimum basilicum*, *Ocimum canum*, and *Ocimum kilimandscharicum*, were evaluated using C57BL and Swiss albino mice tumorigenesis; growth inhibition has in fact been associated with (a) reduction of tumor volume (b) blockage of messengers of pathways involved in cell proliferation was evident in all the oils but the greater was shown by that obtained from *Ocimum tenuiflorum* (syn. *O. sanctum*) compared to other *Ocimum* species. In various experiments and test systems, some mono-and sesquiterpenes showed activity, where camphor, 1,8-cineole and limonene were of greatest interest. Camphor, 1,8-cineole and limonene, the anti-inflammatory compound of *Ocimum kilimandscharicum* oil, showed a strong time-and dose-dependent cytotoxic effect on human ovarian cancer cell [111]. The potential antitumor effects of camphor have been shown previously [112, 113], and the mechanistic action of camphor against cancer included the improvement of immune function [114] and the radiosensitizing effect on transplantable mammary adenocarcinoma in mice [112]. Ursolic acid showed some potentiating effect on the anticancer activity of rosmarinic acid, cinnamic acid, caffeic acid, sinapic acid, and ferulic acid on various cell lines [106].
