*2.2.2 Antioxidant activity*

Various in vitro studies revealed that garlic extract exhibited antioxidant activities in DPPH, ABTS, FRAP, H2O2 scavenging assay, and Fe2+ chelating assays [42–44]. It was reported that storage of garlic for long days accumulated higher level of antioxidant than the fresh ones and shows higher antioxidant activities. However, the postharvest conditions and storage time garlic affect the extent of their antioxidant activities. Usually, fresh garlic had a stronger antioxidant activity than cooked and

*Bioaccessibility, Bioavailability, Antioxidant Activities and Health Beneficial Properties of Some… DOI: http://dx.doi.org/10.5772/intechopen.109774*

fermented garlic [45]. Other than radical scavenging activities earlier studies of garlic extract showed that antioxidant activities of garlic compounds resulted the expression of some antioxidant enzymes, such as heme oxygenase-1 (HO-1), stimulating the activities of antioxidant enzyme activities, and the regulation of the Nrf2-ARE pathway [46]. Earlier studies indicated that garlic saponins scavenge intracellular reactive oxygen species (ROS) and also protect DNA damage induced by H2O2.

#### *2.2.3 Anti-inflammatory activities*

Garlic offers anti-inflammatory benefits because of the presence of various diallyl disulfide compound that controls the effects of pro-inflammatory cytokines [47, 48]. Garlic has great potential to treat inflammatory diseases including arthritis in humans [49]. *In vitro* and *in vivo* experiments studies reported that garlic could inhibit inflammation mainly by inhibiting inflammatory mediators, such as NO, TNF-α, and IL-1 [47].

#### *2.2.4 Anticancer activities*

Several research studies indicated that garlic organosulfur compounds displayed anticancer activities via the inhibiting the cell proliferation and inducing apoptosis of cancer cells both in human culture as well as animal models [50]. Garlic active constituents could protect against diverse cancers, such as colorectal, lung, gastric, and bladder cancers [51–53]. These compounds showed anticancer activities by suppressing cell growth and proliferation and exhibited an anti-proliferative effect on human cancer cell lines, such as liver (HepG2), colon (Caco2), prostate (PC-3), and breast (MCF-7) cancer cells [39]. Moreover, the anticancer properties of garlic occur via the regulation of carcinogen metabolism, induction of apoptosis, suppression of angiogenesis, and inhibition of invasion and migration [39, 44].

#### *2.2.5 Antidiabetic activity*

Garlic supplements were effective in the management of type 2 diabetes mellitus. Garlic has been shown to reduce pancreatic cell injury, oxidative stress, and pathological changes in streptomycin-induced type 1 diabetic rats. Results from the metaanalysis performed on 768 patients with type 2 diabetes mellitus in nine randomized controlled trials showed that garlic supplements significantly reduced fructosamine and glycosylated hemoglobin [54]. Fermented garlic products had certain positive effects on obesity by inhibiting lipogenesis and regulating lipid metabolism [55].

#### *2.2.6 Antimicrobial activities*

Several research study reported that garlic extract showed antibacterial activities by inhibiting the growth of *Staphylococcus aureus*, *Escherichia coli*, and *Bacillus subtilis* [56]. Garlic extract compounds also showed antifungal activities by inhibiting the growth of fungus *Penicillium funiculosum* [57]. In a clinical trial, the treatment of raw garlic inhibited *Helicobacter pylori* in the stomach of patients with *H. pylori* infection [58].

#### *2.2.7 Cardiovascular protection*

Multiple research studies indicated that consumption of garlic and its compounds effectively reduced blood pressure, total cholesterol, low-density lipoprotein cholesterol, and cardiovascular complexities [59]. Garlic derived compounds reduced oxidative stress, increased the regulation of endothelial nitric oxide (NO), and stimulated the production of the vascular gasotransmitter hydrogen sulfide (H2S), and inhibited the angiotensin converting enzyme [39, 60]. These could affect to induce smooth muscle cell relaxation, vasodilation, and lower hypertension.

### **2.3 Ginger (***Zingiber officinale* **Rosc)**

### *2.3.1 Bioactive compounds*

Major bioactive compounds of gingers comprise of phenolic and terpene compounds [61]. Among the phenolic compounds gingerols, shogaols, and paradols are found to be major ones. In fresh ginger gingerols are available in different forms such as 6-gingerol, 8-gingerol, and 10-gingerol [62, 63]. Ginger is dried and stored for long time after harvesting for commercial purpose. During long time storage gingerols are transformed into corresponding shogaols and shogaols transformed into paradols [64]. Ginger contains several phenolic and terpenoids compounds such as quercetin, zingerone, gingerenone-A, 6-dehydrogingerdione, β-bisabolene, *α*-curcumene, zingiberene, *β*-farnesene, and *β*-sesquiphellandrene, which are major part of ginger essential oils [62]. Also, polysaccharides, lipids, organic acids, and raw fibers are other important compounds available in ginger.
