Twenty-five RCTs (n=1817) involving 11 herbal medicinal products were identified. Six RCTs (n=388) involved guggul; 5 RCTs (n=140) used fenugreek seeds; 1 RCT (n=20) used fenugreek leaves; 4 RCTs (n=773) used red yeast rice; 2 RCTs (n=183) used artichoke; 7 RCTs (313) used other herbs. However, there seemed to be a discrepancy in the numbers of participants tabulated in the paper compared with those given online.
Thirteen of the 25 RCTs were assessed to be of low methodological quality with a score of below 3. The reductions in total serum cholesterol ranged from 10 to 33% for all herbs considered together; the main results for the individual herbs were also given.
Guggul: the 5 studies that measured TC found reductions of 10 to 27% in comparison with baseline measures.
Fenugreek: statistically-significant reductions in TC of between 15 and 33% were demonstrated for fenugreek seeds (5 studies). The single study of fenugreek leaves found a non significant reduction of 9% in TC after a single dose, compared with a reduction of 2.8% with placebo (dilute coffee extract).
Red yeast rice (4 studies): there were statistically-significant reductions in TC of 16 to 31%, compared with placebo or control or baseline.
Artichoke (2 studies): one study showed reductions in TC of 18.5% and 8.6% for artichoke and placebo, respectively. The other study found no significant difference in lipid levels in comparison with placebo, although subgroup analyses showed reductions in some groups of participants.
Other herbs: eggplant, arjun, Asian ginseng, holy basil, yarrow and silymarin. Of the 2 studies of eggplant, one showed a reduction in TC of 6.8% from baseline while the other showed an increase of 23%. The study using arjun showed a reduction in TC from baseline of 9.7%. Neither of the 2 studies using Asian ginseng showed any change from baseline, while for holy basil the reduction was 7.6% and for yarrow it was 39%. For silymarin there was a 2.6% increase in TC from baseline.
In terms of safety, mild adverse events were described for all of the herbs and there was the possibility of some drug interactions with guggul, fenugreek, Asian ginseng and silymarin (full details provided in the paper).