## 2 Phytonutrients
### Antimicrobial  
* Antiviral  
Several studies have shown the antiviral effect of garlic. Pre-clinical studies elucidated that garlic and its organosulfides phytochemicals have great activity against several human and animal viruses by inhibiting viral RNA polymerase, reverse transcriptase, and downregulation of the extracellular-signal-regulated kinase/mitogen-activated protein kinase signaling pathway [116]. The variety of viruses attacked by garlic are adenovirus [117]; SARS-CoV-1 [118]; dengue [119]; herpes simplex [120] influenza A, B, and H1N1 [121; 122]; hepatitis [123]; HIV [124]; and rotavirus [125]. Furthermore, in a very recent study, essential garlic oil was found to be acting on the angiotensin-converting enzyme 2 (ACE2) and largely on the main protease of SARS-CoV-2 (PDB6 LU7). This activity is crucial to diminish the impact of the host receptor of SARS-CoV-2, and this study proposes that garlic oil active compounds can be used as a COVID-19 preventive treatment [126]. * Antibacterial  
The antibacterial effect of garlic was analyzed in vitro using fresh garlic juice in agar plates against _E. coli_, _P.mirabilis_, _K.pneumoniae_, _S.areus_, and _P.aeruginosa_. The results showed a dose-dependent inhibition in all bacterial strains exposed to a garlic concentration higher than 10% [127]. In another study, two different aqueous garlic extracts (from _Allium sativum_ and _Allium tuberosum_) were tested in rats infected with one penicillin-sensitive (ATCC 25923) and one methicillin-resistant (ATCC 33592) _S. aureus_. The two species of garlic were administered orally at 100 and 400 mg/kg) every 6 hours for 24 hrs. Results showed that both garlic extracts could reduce the infection but not against the resistant strain [128]. Several in vitro studies demonstrated the antibacterial effect of fresh garlic extract on _E. coli_, _Klebsiella pneumoniae_, _Proteus mirabilis_, _P. aeruginosa_, and _S. aureus_[127], and also against multidrug-resistant _E. coli_, _P. aeruginosa_, _K. pneumoniae_, _Serratio marcscens_, and methicillin-resistant _S. aureus_[129]. In a clinical trial that involved 15 patients with _Helicobacter pylori_, the results showed that the urease breath test to detect _H. pylori_ was lower in patients who took 3 g of garlic closes twice a day, demonstrating its antimicrobial effect [130]. Antifungal  
Various studies have discussed the antifungal effect of garlic. [PERSON] et al. showed that garlic oil had an inhibitory effect against _Candida albicans_ at a concentration of 0.35 \(\upmu\)g/mL [131]. [PERSON] et al. performed an experiment that evaluated the structural characteristic of _Trichophyta rubrum_ in response to garlic and allicin aqueous extracts. The results showed that the allicin extract was more effective in impeding the growth of fungal cells by changing fungi morphology [132]. Another in vitro study indicated that 0.125 and 0.0313 % of garlic oil had a strong antifungal activity by penetrating hyphae cells and destroying their organelles against _Penicillium funiculosum_[133]. Anti-Inflammatory  
The anti-inflammatory effect of garlic was studied by several research groups. Overall, the studies agreed on the antioxidant and anti-inflammatory properties of garlic. However, the results for the mechanisms activated/inhibited by the phytonutrients themselves and their phytochemicals are diverse. We understand that this could be possible due to different garlic preparations and also by the \"double-edged sword\" of nitric oxide. For example, in an in vitro study, [PERSON] and coworkers showed garlic's anti-inflammatory activity at \(\upmu\)M concentrations. They demonstrated that garlic's organosulfides Z- and E- ajoene and analogs inhibited nitric oxide/prostaglandins and nitric oxide synthase/cyclooxygenase, the phosphorylation of p38 mitogen-activated protein kinases, and, also, the expression of the following pro-inflammatory cytokines: tumor necrosis factor-\(\alpha\), interleukin-1\(\beta\), and \(-6\) in a lipopolysaccharide-anchardide-induced macrophage cell line [134].