What is caralluma fimbriata

Caralluma fimbriata is an edible succulent cactus, which belongs to the family Asclepiadaceae grows wild all over India ¹⁾. Caralluma fimbriata has been used by tribal Indians as a portable food and thirst quencher for hunting. Caralluma fimbriata is also used for its purported ability to suppress hunger and appetite and enhance endurance ²⁾. Tribesmen on a day’s hunt will often only pack some Caralluma fimbriata to sustain themselves and hence it is commonly considered a “famine food” in India.

Caralluma fimbriata key ingredients are pregnane glycosides, flavone glycosides, megastigmane glycosides, bitter principles, saponins and various other flavonoids ³⁾. The appetite suppressant action of Caralluma fimbriata could be mainly attributed to the pregnane glycosides. These compounds seem to have peripheral and central effects. In the adipose tissue, pregnane glycosides reduce lipogenesis ⁴⁾. In the central structures regulating appetite, pregnane glycosides and its related molecules seem to share a similar mechanism of that of Hoodia gordonii where they act by amplifying the signalling of the energy sensing function in the hypothalamus ⁵⁾.

Caralluma fimbriata is an erect branched herb, 20-30 cm tall. Stems are leafless, 4-angled, fleshy, green, tapering to a point. Leaves are minute, present only on young branches, soon falling off, leaving a tooth-like projection on the angles. Flowers are borne at the end of branches, singly or 2-3 together on short stalks. Flowers are like wheels, 2 cm across. Petals are narrow, purple with yellow marking, and margins frilly with hairs. Fruits are 10-12 cm long, cylindric with one of the pairs often suppressed. Caralluma is found in peninsular India. It has been eaten in rural India for centuries, raw, as a vegetable with spices, or preserved in chutneys and pickles, and is often found as a roadside shrub or boundary marker.

Figure 1. Caralluma fimbriata

The effect of Caralluma fimbriata extract was assessed in overweight individuals by a placebo controlled randomized trial. Fifty adult Indian men and women (25–60 years) with a body mass index (BMI) greater than 25 kg/m² were randomly assigned into a placebo or Caralluma fimbriata extract group who received 1 g of Caralluma fimbriata extract per day for 60 days. All subjects were given standard advice regarding a weight reducing diet and physical activity. At the end of 30 and 60 days of intervention, blood glucose and lipids, anthropometric measurements, dietary intake and assessment of appetite was performed. Waist circumference and hunger levels over the observation period showed a significant decline in the Caralluma fimbriata extract group when compared to the placebo group ⁶⁾. While there was a trend towards a greater decrease in body weight, body mass index, hip circumference, body fat and energy intake between assessment time points in the experimental group, these were not significantly different between experimental and placebo groups ⁷⁾. Caralluma fimbriata extract appears to suppress appetite, and reduce waist circumference when compared to placebo over a 2 month period ⁸⁾.

In a randomized, double blind placebo controlled clinical trial, forty-three adults aged 29-59 years were recruited. The eligibility criteria included a Body Mass Index (BMI) >25 kg/m², or a waist circumference >94 cm (male), >80 cm (female) ⁹⁾. Thirty-three participants completed the 12-week study at Victoria University Nutritional Therapy Clinic. Participants were randomly assigned into two groups. Caralluma fimbriata extract and placebo were orally administered as 500 mg capsules twice daily (1 g/day) and dietary intake and exercise were monitored weekly. The results of thirty-three participants (Caralluma fimbriata extract group, n = 17; placebo group n = 16) were analyzed. The primary outcome measure was the decline in waist circumference. By week 9, the Caralluma fimbriata extract group had lost 5.7 cm, compared to only 2.8 cm loss in the placebo group. Post intervention, the Caralluma fimbriata extract group had lost 6.5 cm compared to 2.6 cm loss in the placebo group. Waist to hip ratio also improved significantly after 12 weeks intervention in the experimental group, with a total reduction of 0.03 being recorded compared to 0.01 increase in the placebo group. There was also a significant decline in the palatability (visual appeal, smell, taste) of the test meal and sodium intake in the Caralluma fimbriata extract group at week 12. In addition a significant reduction in body weight, BMI, hip circumference, systolic blood pressure, heart rate, triglyceride levels, total fat and saturated fat intake within both groups was observed following the intervention period ¹⁰⁾. Supplementation with caralluma fimbriata extract whilst controlling overall dietary intake and physical activity may potentially play a role in curbing central obesity, the key component of metabolic syndrome.

On the negative side, another randomized controlled study ¹¹⁾ involving 89 volunteers divided into two groups, to receive either Caralluma fimbriata extract (Cap S available commercially 500 mg) of the same batch of manufacturing (1 g daily)/oral for 12 weeks or matching placebo. Caralluma fimbriata extract dose selection of the test drug used was made from the available clinical study ¹²⁾. The placebo group was similarly administered placebo in the form of 2 identical capsules to Caralluma fimbriata extract twice a day/oral for 12 weeks. All subjects were also provided with the same standard advice regarding diet and physical activity.

Patients were evaluated clinically and biochemically in current single blind study where patients were blind to treatment for a period of 3 months at 4, 8 and 12 weeks for anthropometric measurements (weight, waist circumference, hip circumference, waist hip ratio, BMI); appetite assessment using visual analog scales (VAS) for “hunger”, “thoughts of food”, “urge to eat” and “fullness of stomach” ¹³⁾. Biochemical investigations like lipid profile (Total cholesterol, low-density lipoprotein cholesterol [LDL bad cholesterol], high-density lipoprotein cholesterol [HDL good cholesterol], very-low-density lipoprotein [VLDL], total triglycerides), blood glucose (fasting/postprandial), liver function tests (Total protein, Serum Bilirubin, aspartate aminotransferase [AST], alanine aminotransferase [ALT] and alkaline phosphatase [ALP]), renal function tests (serum creatinine and serum urea), complete blood counts (hemoglobin [Hb], total leukocyte count, platelet count) were undertaken. Other parameters evaluated include blood pressure, pulse rate, electrocardiography (ECG) and recording of any adriamycin during the study period. Compliance was assessed on basis of number of drop outs and capsule counts done 4 weekly.

Evaluation of the data generated from that current study ¹⁴⁾ revealed that Caralluma fimbriata extract did not lead to any significant reduction in weight and BMI during the 12 weeks of the study. When compared with the placebo group no significant difference was observed at any time point during the study period.

Waist circumference is at least as good an indicator of total body fat as BMI and is also the best anthropometric predictor of visceral fat. Hip circumference is another important anthropometric parameter. Effect of Caralluma fimbriata extract on these anthropometric parameters (waist circumference and hip circumference) in that current study also did not lead to any significant reduction in waist circumference and hip circumference during the 12 weeks of the study ¹⁵⁾. The WHR is a robust measure of risk in many population studies and has been suggested to be a superior predictor of cardiovascular disease risk. In the same study, evaluation of waist hip ratio revealed that it almost remained static over the entire period of the study ¹⁶⁾. When compared with the placebo group no significant difference was observed at any time point during the study period.

Appetite assessment based on VAS in the current study failed to yield any positive results with Caralluma fimbriata extract. No significant differences were observed in the change of “hunger”, “thoughts of food”, “urge to eat” and “fullness of stomach” over a period of 12 weeks when compared to baseline both in the test and placebo group, however, a numerical improvement in all the parameters could be appreciated in both the groups ¹⁷⁾. Furthermore, there were no significant differences observed in the change of appetite on comparative analysis between the test and placebo group ¹⁸⁾. Kuriyan et al. ¹⁹⁾ however, in their study reported a significant decline in the hunger levels in the experimental group when compared to the placebo group. A small sample size in their study could have led to disparity with the current study results ²⁰⁾.

The results of this clinical study ²¹⁾ using commercially available extract of Caralluma fimbriata in an oral dose of 1 g/day for 12 weeks has failed to yield any positive results on anthropometry and appetite in overweight and obese patients. The current study underscores the need to carry more research before Caralluma fimbriata extract is recommended as an anti-obesity drug in the clinical practice. The negative anti-obesity results seen with Caralluma fimbriata extract in the current study open up a new debate about method of issuing regulatory approval to manufacture and sale any product without much of the existing scientific evidence in its favor ²²⁾.

Caralluma fimbriata side effects

Arora et al. ²³⁾ study explored product safety in the form of clinical evaluations and reported adverse events. The biochemical and clinical parameters of the subjects belonging to Caralluma fimbriata extract group showed no alterations at different assessment points of the study. Furthermore, no significant differences were observed on comparative analysis between the Caralluma fimbriata extract and placebo group. Most adverse events reported by patients in their study were mild in severity and transient in nature. The observed adverse events in their study were nausea, palpitation, glossitis, insomnia, generalized weakness and constipation ²⁴⁾. No significant differences were observed between placebo and Caralluma fimbriata extract groups in number of reported adverse events and no subjects were removed from the study for a treatment-related adverse event ²⁵⁾. However, strangely one known case of hypertension presented with exacerbation of blood pressure which was transient in nature and was controlled. The patient continued with Caralluma fimbriata extract with no recurrence of the adverse event during the entire period of the study. In a similar way studies by Kuriyan et al. ²⁶⁾ and Lawrence and Choudhary ²⁷⁾ also reported no serious adverse event with the use of Caralluma fimbriata extract.

Toxicological assessment evaluated the safety of a hydroethanolic extract prepared from Caralluma fimbriata (caralluma fimbriata extract), a dietary supplement marketed worldwide as an appetite suppressant. Studies included 2 in vitro genotoxicity assays, a repeated dose oral toxicity study, and a developmental study in rats. No evidence of in vitro mutagenicity or clastogenicity surfaced in the in vitro studies at concentrations up to 5000 μg of extract/plate (Ames test) or 5000 μg of extract/mL (chromosomal aberration test) ²⁸⁾. No deaths or treatment-related toxicity were seen in the 6-month chronic oral toxicity study in Sprague-Dawley rats conducted at 3 doses (100, 300, and 1000 mg/kg body weight/day) ²⁹⁾. The no observed effect level for caralluma fimbriata extract in this study was considered to be 1000 mg/kg body weight/day. A prenatal developmental toxicity study conducted at 3 doses (250, 500, and 1000 mg/kg body weight/day) in female Sprague-Dawley rats resulted in no treatment-related external, visceral, or skeletal fetal abnormalities, and no treatment-related maternal or pregnancy alterations were seen at and up to the maximum dose tested ³⁰⁾. Caralluma fimbriata extract was not associated with any toxicity or adverse events.