Garlic (Allium sativum) has potential therapeutic effects against respiratory tract infections, intra‐alveolar edema and cell infiltration, pulmonary fibrosis, sepsis, and acute lung injury. Garlic along with its bioactive compounds, s‐allyl cysteine (SAC), alliin, and diallyl thiosulfonate (allicin), has been shown to have antiviral, antifibrotic, antioxidant, antiinflammatory, and immunomodulatory properties (Arreola et al., 2015; Bayan, Koulivand, &Gorji, 2014; Shang et al., 2019).The presence of sulfur-containing phytochemicals in garlic (Allium sativum L.) provides substantial immunomodulatory, anti-inflammatory, anticancer, antitumor, antidiabetic, anti-atherosclerotic, and cardioprotective features.
Not only this, garlic has significantly inhibited pulmonary fibrosis and acute lung injury, and subsequently mitigated oxidative stress and inflammatory response in chemically induced pulmonary fibrosis, sepsis, and acute lung injury rat models. For example, in multiple studies using either bleomycin‐ or carbon tetrachloride (CCl4)‐induced pulmonary fibrosis rat model, SAC significantly reduced the fibrotic lesions, alveolar wall thickening, and collagen deposition. In doing so, it reduced the expression of various collagens, fibronectin, as well as levels of various fibrotic markers including hydroxyproline, α‐SMA, and TGF‐β, possibly by inhibiting phosphoinositide 3‐kinases (PI3K)/protein kinase B (AKT) and nuclear factor‐κB (AKT/NF‐κB) signaling pathways (Nie et al., 2019). SAC also reduced inflammatory cells in the alveolar spaces and attenuated lung injury by reducing the expression of inflammatory genes namely iNOS, TNF‐α, and matrix metalloproteinase‐9 (MMP‐9), and reducing levels of oxidative stress markers like inducible NO synthase (iNOS) in lungs, total nitrites and nitrates (NOx), ROS, and lung lipid peroxides (Mizuguchi et al., 2006; Tsukioka et al., 2017).
Along the same lines, allilin (SAC sulfoxide) was shown to inhibit alveolar edema and damage, reduce neutrophils infiltration into alveoli and decrease inflammatory cytokines like TNF‐α and IL‐1β. In this process, allilin also inhibited the inflammatory response by inhibiting NF‐κB and peroxisome proliferator‐activated receptor γ (PPARγ) in lipopolysaccharides induced acute lung injury rat model (Wang, Guo, He, Chen, & Zhuang, 2017). Similarly, in CLP‐induced sepsis and acute lung inflammation models in rats, SMFM (sucrose methyl 3‐formyl‐4‐methylpentanoate) a natural compound isolated from garlic significantly inhibited alveolar damage, thrombotic lesions, and lung infection. In addition, SMFM also inhibited bacterial infection and proinflammatory cytokines TNF‐α, IL‐6, and IL‐1β in the peritoneal fluid which are known to cause vital organ damage (Lee et al., 2015).
Garlic is also a potent immunomodulator (Ishikawa et al., 2006). In a clinical study on humans, dietary consumption of 2 g of garlic every 2–3 days, boosted the basal plasma IFN‐α levels which are known to be protective against viral infections and prevent viral replication (Bhattacharyya, Girish, Karmohapatra, Samad, & Sinha, 2007). Importantly, these pre‐clinical studies highlight the efficacy of garlic in mitigating pulmonary fibrosis, lung injury, and sepsis‐associated organ failure, all of which are symptoms observed in patients with advanced COVID‐19 infection.
UIN: 82HP31R