Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials

Abstract

Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials The purpose of this study was to determine the effect of 2 concentrations of topical, comfrey-based botanical creams containing a blend of tannic acid and eucalyptus to a eucalyptus reference cream on pain, stiffness, and physical functioning in those with primary osteoarthritis of the knee. Methods: Forty-three male and female subjects (45-83 years old) with diagnosed primary osteoarthritis of the knee who met the inclusion criteria were entered into the study. The subjects were randomly assigned to 1 of 3 treatment groups: 10% or 20% comfrey root extract (Symphytum officinale L.) or a placebo cream. Outcomes of pain, stiffness, and functioning were done on the Western Ontario and MacMaster Universities Osteoarthritis Index. Participants applied the cream 3× a day for 6 weeks and were evaluated every 2 weeks during the treatment. Results: Repeated-measures analyses of variance yielded significant differences in all of the Western Ontario and MacMaster Universities Osteoarthritis Index categories (pain P b .01, stiffness P b .01, daily function P b .01), confirming that the 10% and 20% comfrey-based creams were superior to the reference cream. The active groups each had 2 participants who had temporary and minor adverse reactions of skin rash and itching, which were rapidly resolved by modifying applications. Conclusion: Both active topical comfrey formulations were effective in relieving pain and stiffness and in improving physical functioning and were superior to placebo in those with primary osteoarthritis of the knee without serious adverse effects.

A critical scoping review of external uses of comfrey (Symphytum spp.)

“…Studies are summarised in Tables 1 and 2 for efficacy and adverse events, respectively. All studies evaluated developing or established commercial comfrey creams; eight evaluated Kytta-Salbe ® (Merck Selbstmedikation GmbH, Darmstadt; S. officinale fresh root and rosemary oil), 41,42,49,51,52,56,62 one S. officinale (part not specified), eucalyptus oil and tannic acid (4Jointz ® ; Arthritis Relief Plus Ltd, Brisbane), 47 one including various S. officinale preparations, 57 eleven Traumaplant ® (Harras Pharma Curarina GmbH, München; S. x uplandicum fresh leaf) [43][44][45][46][53][54][55]59,[63][64][65] and five combined products including Symphytum species (plant part unknown) with other herbal extracts including mistletoe (Syviman ® ; Müller Göppingen, Wegenerstr), 48 walnut (Phytoskin ® ; Vita-Cos-Med KlettLoch GmbH, Eisenberg) 66 and calendula, sage and yarrow (Plantoderm ® 50,58 Zdravlje-Actavis Pharmaceutical Company, Leskovac; and Antiacne ® 61 Fontis Ltd., Podgorica). 1 No clinical trials were located for S. asperum.…”

“…1 No clinical trials were located for S. asperum. Study comparators included placebo, 41,42,[47][48][49]51,53 reference cream containing a concentration of 1% comfrey (active group 10% concentration), [43][44][45][46] an area of skin without the cream, 56 and usual care or an alternative treatment. 50,52,54,55,58 In one 1 Products and manufacturers are listed here as in the included publication.…”

“…Twenty one studies included an objective to assess adverse events or tolerability (tolerability was assumed to relate to adverse events) -11 RCTs, [41][42][43][44][45][46][47][48][49][50]52 two CCTs 54,55 and eight OSs. [59][60][61][62][63][64][65][66] Twenty of these provided tolerability outcome data.…”

“…[59][60][61][62][63][64][65][66] Twenty of these provided tolerability outcome data. [41][42][43][44][45][46][47][48][49][50]52,54,55,[59][60][61][62][64][65][66] Nineteen reported the incidence of AEs [41][42][43][44][45][46][47][48][49][50]52,54,55,[59][60][61][62]64,66 and five provided information about the AE data collection method. [43][44][45][46]…”

Medicinal herbs as possible sources of anti-inflammatory products

“…Also, the results were superior to the reference eucalypt cream. Side effects were rash and itching that has been resolved quickly by changing applications [37]. Furthermore, an ointment with comfrey was compared with diclofenac gel in the treatment of acute sprains of the unilateral ankle (4 applications / day for 7 days).…”