Table 2.

The examples of clinical studies of natural products.

Natural Product	Experimental Design	Dosage	Comments	Reference
Curcumin	160 patients with solid tumor were given Meriva as an adjuvant to chemotherapy.	1500 mg/day of Meriva in three separate doses for six weeks.	Patients’ quality of life was improved, and systemic inflammation was significantly reduced.	[354]
	Patients with colorectal cancer were orally provided curcuma extract.	Up to 2.2 g daily (equal to 180 mg of curcumin) for several months.	Curcumin was proven to accumulate at the colorectum and acquire the effective therapeutic concentration.	[356]
	33 patients with benign prostatic hyperplasia were given Meriva.	1000 mg/day in two divided doses) for 2 years.	Improvements in all categories of the International Prostate Symptom Score.	[357]
	Patients with familial adenomatous polyposis were given a combination of curcumin and quercetin.	480 mg curcumin and 20 mg quercetin orally three times daily for six months.	The quantity and size of malignant polyps were dramatically reduced.	[359]
	25 patients with advanced pancreatic cancer were given curcumin capsules.	8 g of curcumin capsules daily, with restaging every eight weeks.	Oral curcumin had biological action and was safe in some pancreatic cancer patients.	[360]
Resveratrol	39 women with a high risk of breast cancer.	For 12 weeks, the participants were given two capsules per day containing either placebo, 5 mg of trans-resveratrol, or 50 mg of trans- resveratrol.	PGE2 levels were discovered to be reduced.	[365]
	Patients with colon cancer were given low-dose resveratrol and resveratrol-containing freeze-dried grape powder.	Low-dose resveratrol (80 mg/d) and resveratrol-containing freeze-dried grape powder (80 g/day for 14 days of treatment).	There was an increase in the expression of Myc and cyclin D1 in colon cancer tissue.	[367]
	Micronized resveratrol (SRT501) was given to individuals with colorectal cancer and hepatic metastases.	Micronized resveratrol (SRT501) was given at a dose of 5 g/day for two weeks.	SRT501 was well tolerated and increased mean plasma resveratrol levels (3.6-fold) after a single dosage compared to non-micronized resveratrol.	[369]
EGCG	481,563 volunteers aged 51–71 years were given hot tea.	1 cup/day or more of hot tea drinking for up to eight years of follow-up.	This study revealed a statistically significant inverse connection between hot tea drinking and risk of pharyngeal cancer.	[374]
	59 patients with oral mucosa leukoplakia were given green tea extract.	3 g mixed tea oral administration and topical treatment for six months.	37.9% of patients who received green tea treatment had smaller oral lesions.	[375]
	Assessment the relationship between green tea consumption and colorectal cancer risk on 69,710 Chinese women aged 40 to 70 years.	2–3 cups/day of green tea for up to 3 years of follow-up.	The study indicated that drinking tea on a regular basis considerably lowered the incidence of colorectal cancer.	[377]
	10 female patients (38–55 years old) with locally advanced noninflammatory breast cancer undergoing radiation were given EGCG capsules.	EGCG capsules (400 mg) were orally provided three times daily for two to eight weeks.	EGCG was discovered to increase the efficacy of radiotherapy in breast cancer patients, raising the possibility of EGCG being used as a therapeutic adjuvant in the treatment of metastatic breast cancer.	[378]
	42 patients with androgen-independent prostate cancer were given green tea.	6 g/day of green tea were provided orally in 6 divided doses for 2 months.	One of the patients demonstrated a 50% decrease in prostate-specific antigen (PSA) level.	[380]
	Patients with prostate cancer were prescribed green tea extract capsules.	Green tea extract capsules were given at a dose level of 250 mg twice daily for 2 months.	40% of patients who finished the treatment showed delayed disease progression.	[381]
	451 patients with pancreatic cancer were given green tea.	200 g/month of green tea were provided for 3 years.	The study lowered the risk of pancreatic cancer.	[383]
Allicin	51 patients with colorectal adenomas were given aged garlic extract.	2.4 mL/d of aged garlic extract for 12 months.	Aged garlic extract was related with a significantly lower risk of developing new colorectal adenomas.	[388]
	2526 persons with family history of stomach cancer were given allitridum and selenium.	200 mg synthetic allitridum every day and 100 microg selenium every other day for 2 years.	High dosages of allitridum and microdoses of selenium have been found to prevent stomach cancer, particularly in men.	[390]
	343 patients with esophageal squamous cell carcinoma and 755 cancer-free controls ingested raw garlic/onions.	Raw garlic/onions were given at least once per week for 10 years.	Raw onions/garlic were significantly protective against esophageal squamous cell carcinoma.	[393]
Genistein	9000 breast cancer patients were given soy food.	19.1 mg/day of soy food was given for up to 10 years.	Study found that increasing the genistein dose reduced breast cancer risk.	[396]
	23 prostate cancer patients received genistein before radical prostatectomy.	30 mg synthetic genistein was given daily for up to 6 weeks.	The level of the prostate cancer biomarker prostate-specific antigen in blood was reduced.	[398]