**5.** *Curcuma longa* **(turmeric) – Antiviral and anti-inflammatory**

### **5.1 Turmeric in COVID-19**

Turmeric has antiviral and anti-inflammatory effects that might benefit COVID-19 patients [10, 13]. It has also been hypothesized that the antioxidant effects of turmeric benefit diabetic patients during COVID-19 infection [67]. However, some has expressed concerns that curcumin, the main active component of turmeric, might increase the expression of ACE2 and worsen COVID-19 infection as well as increase pro-inflammatory cytokines and worsen COVID-19 in patients with cytokine storm [26]. In the contrary, curcumin binds to viral S protein and the viral attachment sites of the ACE2 receptor protein to inhibit the entry of SARS-CoV2 [18, 68]. In addition, curcumin has shown to reduce inflammatory cytokines in COVID-19 patients. In a clinical study with 40 COVID-19 patients, curcumin given as nano-curcumin at 160 mg/day for 14 days reduced the inflammatory cytokines IL-6 and IL-1β as well as clinical manifestations (fever, cough, dyspnea, headache, chest radiography, lymphocyte, white blood cells, and platelets count) in comparison to placebo-treated group. Both groups were taking atorvastatin, bromhexine, and betaferon concomitantly with 5–15% of them having diabetes, cardiovascular disease or renal disease. These results suggest the effectiveness and safety of curcumin in COVID-19 patients with underlying medical conditions [69].

#### **5.2 Turmeric in diabetes**

In clinical trials with type 2 diabetic patients, curcuminoids from 250 mg/day for 9 months to 1 g/day for 3 months improved glycemic control, β-cell function, insulin resistance, and reduced inflammatory cytokines with no major adverse effects. Minor side effects included diarrhea, constipation, vertigo, and itching. Some clinical and preclinical studies also showed that curcumin improve biomarkers of liver and kidney damage [70]. In a clinical trial on 46 patients with diabetic nephropathy, 1.5 g curcumin for 16 weeks improved 24-h urine analysis for albuminuria with no change in blood urea nitrogen, creatinine, fasting blood sugar, 2-h postprandial blood sugar, lipid profile, serum albumin, and hemoglobin A1C in comparison to placebo and baseline [71].
