Table 2

Summary of interventions

Study first author, year, reference	Study design	Inclusion criteria	Preparation of tumeric/curcumin	Control intervention (type)	Rescue intervention (dose)
Panda (2018)26	RCT with two parallel groups	40 to 75 years old BMI of 18 to 30 kg/m2. OA of the knee for greater than 3 months (ACR criteria) KL grade 2 or 3 Female subjects of childbearing potential must be using a medically acceptable form of birth control. VAS score between 40 to 70 mm Subjects with pain not adequately controlled with anti-inflammatory drugs Subjects willing to refrain from using ibuprofen, aspirin or other NSAIDs Subjects willing to refrain other pain reliever including topical application (OTC or prescription) and omega-3 fatty acids during the entire trial.	Curene: Bio-optimised turmuric/Curcuma longa extract comprising of curcuminoids developed via Aqueosome technology	Placebo capsules with similar size and shape to intervention	Acetaminophen: 2000 mg per day
Nakagawa (2014)27	RCT with two parallel groups	Primary medial knee osteoarthritis >40 years of age KL grades of 2 or 3	Theracurcumin: a surface-controlled water dispersible curcumin extract with high bioavailability	Placebo capsules with similar size and shape to intervention	Celecoxib 100 mg per day
Madhu (2013)28	RCT with four parallel groups	Age >40 Primary knee OA 3. >6 months of pain 4. KL grades: grades 2 and 3	NR-INF-02 (Turmacin): extract from rhizome of Curcuma longa with increased bioavailability	1. Placebo capsules. 2. Glucosamine 1500 mg per day. 3. NR-INF-02+GS	Acetaminophen: Dose not provided
Belcaro (2010)29	RCT with two parallel groups	Primary osteoarthritis in one or both knees was diagnosed by X-ray. Subjects had mild-to-moderate pain not adequately controlled with anti-inflammatory drugs	Meriva: A mixture of 75 per cent curcumin, 15 per cent demethoxycurcumin and 10 per cent bisdemethoxycurcumin.	‘Best available treatment’	N/A
Shep (2019)30	RCT with two parallel groups	Primary knee OA with ACR criteria confirmed on X-ray Numerical pain VAS scale of knee pain >4/10	Curcumin (BCM-95): containing curcuminoids and essential oil of turmeric complex (curcumin, demethoxycurcumin, bisdemethoxycurcumin and volatile oils from turmeric rhizome)	Diclofenac 50 mg two times per day	Paracetamol 500 mg tablet
Panahi (2014)31	RCT with two parallel groups	Degenerative primary knee OA with mild-to-moderate severity Bilateral OA Age <80 years.	Curcuminoids (C3 complex) with 5 mg of BioPerine pepper extract for increased bioavailability	Placebo capsules with similar size and shape to intervention	Naproxen: Dose not provided
Henrotin (2013)32	RCT with three parallel groups	45 to 80 years old Primary symptomatic knee OA by ACR radiographic findings TVAS of 40 mm (0 to 100 mm scale) 3 months prior to enrolment	Flexofytol: Bio-optimised turmeric rhizome extract	Placebo tablets with similar size and shape to intervention	1. Acetaminophen: up to 500 mg three times per day 2. NSAIDs as secondary rescue
Kuptniratsaikul (2009)33	RCT with two parallel groups	>50 years Morning stiffness >30 min in duration Crepitus on motion. Patients who had a pain score in the numerical rating scale of >5/10	Curcumon domestica extract: Bio-optimised turmeric extract each capsule contained 250 mg of curcurminoids	Ibuprofen at a dose of 800 mg per day	N/A
Kuptniratsaikul (2014)34	RCT with two parallel groups	Primary knee OA patients according to ACR criteria Numerical pain rating scale of knee pain >5/10 Age >50 years.	Curcumin domestica extract: Bio-optimised turmeric extract each capsule contained 250 mg of curcurminoids	Ibuprofen at dose of 1200 mg per day	Tramadol: Dose not provided
Srivastava (2016)35	RCT with two parallel groups	Primary knee OA by ACR criteria Age 40 to 80 years old	Curcumin longa extract	Control group: Placebo capsules+diclofenac 25 mg two times per day	N/A

ACR, American College of Rheumatology; BMI, body mass index; KL grade, Kellgren-Lawrence grade; NSAIDs, non-steroidal anti-inflammatory drugs; OA, osteoarthritis; OTC, over-the-counter; RCT, randomised controlled trial; TVAS, targeted visual analog scale; VAS, Visual Analogue Score.