Skullcap needs to wear quality hat
leading to anomalies in efficaciousness which damage the whole
sector, according to UK researchers.
The University of East London (UEL)scientists found both the dosage and quality of bioactive components in commercially available herbs were highly inconsistent, at least in the skullcap (Scutellaria) products they tested. There are more than 350 skullcap varieties of the versatile herb that has been shown to benefit nervous disorders, liver disease, cancer, joint health and osteoarthritis. Call for quality The researchers said unless some kind of standardisation could be achieved, the category was in jeopardy of shedding large numbers of consumers and revenue. "Wide variability in the biomarker content of herbal preparations undermines the practice of herbal medicine itself," said Dr Olivia Corcoran, lead researcher and head of forensic science at UEL. "There is an urgent need for products to be labelled with accurate assessment of the content of agreed biomarkers. Without such labelling, it is extremely difficult to assess the effects of herbal medicines, many of which are known to be useless in low doses and dangerous in high concentrations." The paper, entitled 'Validation of a HPLC method for flavonoid biomarkers in skullcap (Scutellaria) and its use to illustrate wide variability in the quality of commercial tinctures,' was published in the Journal of Pharmacy and Pharmaceutical Sciences. The researchers said the inconsistency in product quality meant scientific assessment was compromised. Methods They conducted tests to compare the flavonoid biomarker content of eleven commercial tinctures derived from the two most commonly-used species, Scutellaria lateriflora (American skullcap) and Scutellaria baicalensis (Chinese skullcap). Commercial tinctures of both Scutellaria species varied widely in the drug-to-extract ratio (ranging from 1:1 to 1:5) and alcohol concentration (25 per cent to 70 per cent), depending on the manufacturer. The variable efficacy of herbal medicines used in clinical practice as well as those herbal medicines and dietary supplements used in clinical trials and in assays of pharmacological activity, could be explained by the bioactive component variance, the scientists said. Dr Barbara Pendry, programme leader for the BSc in herbal medicine at UEL, said: "These findings once again emphasise the need for the highest standards of academic integrity, diagnostic competence and clinical excellence in the practice of herbal medicine." The authors will present these and other findings at the National Institute for Medical Herbalists (NIMH) conference in the UK next week. Source: 'Validation of a HPLC method for flavonoid biomarkers in skullcap (Scutellaria) and its use to illustrate wide variability in the quality of commercial tinctures,' Journal of Pharmacy and Pharmaceutical Sciences 1 (1): 77-87, 2008 Authors: Olivia Corcoran, Jiayu Gao, Alberto Sanchez-Medina, Barbara A Pendry, Michael J Hughes, Geoffrey P Webb
