Comfrey or Wallwort is an ancient medicinal plant that has been used for centuries to treat musculoskeletal injuries. Although the mechanism of action is still not clear, numerous clinical studies have documented the efficacy and tolerability of topical applications of comfrey. This article also presents a study that, depending on the evaluation, demonstrates the non-inferiority or even superiority of comfrey over diclofenac.
Comfrey – Comfrey – Symphytum
Whether comfrey, comfrey or Symphytum: Behind all three names lies the same medicinal plant: Symphytum officinale (Fig. 1). In German usage, all three names are used. Comfrey is the English name of the plant, which is native to both Europe and North America.
The name comfrey is composed of “leg”, the original name for bone, and the old German verb “wallen”, which means to grow together. And thus the name already expresses how the medicinal plants can be used. For centuries, comfrey has been used to treat injuries and broken bones.
Systemic use is obsolete today because Symphytum officinale contains pyrrolizidine alkaloids that can cause hepatotoxic effects. Likewise, its use on open wounds is contraindicated because it can cause abscesses. Today, extracts from the roots are mostly used. Allantoin and rosmarinic acid are probably the crucial ingredients for the various effects [1]. Allantoin promotes epithelial formation, cell proliferation and is responsible for removing necrosis. However, the actual mechanism of action of Symphytum officinale is not yet clear.
Clinically proven applications
In recent years, a variety of RCT studies have been published demonstrating various therapeutic applications of extracts of comfrey. These include ankle distortions [2], gonarthrosis of the knee joint [3,4], back pain [5], blunt trauma [2,6], and myalgias [7].
Application for children
The efficacy and safety of Symphytum cream in children was reviewed and confirmed in an observational study [8]. In this study, 196 four- to 12-year-old children diagnosed with blunt trauma had comfrey ointment applied to the affected areas three times a day. To assess for efficacy, palpitation pain, functional disability, edema, and hematoma were considered. The mean treatment duration was 7.6 ± 1.1 days. Remission rates for the criteria assessed were 86.3% for palpitation pain, 86.7% for movement pain, 89.7% for functional disability, 94% for edema, and 90.1% for general disability. No adverse drug reactions were observed with these treatments.
Comparison with Diclofenac
As an example of the clinical studies mentioned above, the study by Predel et al. from 2005 [4] was presented: This involved the comparative efficacy of a comfrey gel and a diclofenac gel for the treatment of ankle sprains. In this single-blind, controlled, randomized, multicenter, parallel-group study, 164 patients with a diagnosed unilateral ankle sprain were treated. They were applied either a 6-cm strand of comfrey cream (n=82) or a diclofenac gel containing 1.16 g of diclofenac diethylamine salt (n=82) four times daily for seven days. The basis of assessment was the pressure pain on the injured site generated on days 0,4 and 7 using a calibrated algometer expressed as AUC (“area under the curve”) on the pain-time curve. The secondary outcome variables were joint swelling measured as circumference and by the figure-of-eight method, individual spontaneous pain sensation at rest and during movements expressed as VAS (=visual analog scale), total assessment, and assessment of tolerance of topical applications. The 95% CI (“confidence interval”) for AUC (comfrey extract minus diclofenac gel) was clearly above the margin of noninferiority for comfrey versus diclofenac, documenting noninferiority of comfrey compared with diclofenac.
After seven days of treatment, the mean reduction at rest was 92% in the comfrey group and 85% in the diclofenac group. The mean reduction in motion at this time point was 83.2% in the comfrey group and 72.4% in the diclofenac group. Comfrey was also found to be superior in the parameters of joint swelling and pressure pain.
A later re-evaluation of the study results [9] according to the guidelines of the Committee for Proprietary Medicinal Products (CPMP, 2002) even documented a superiority of the comfrey preparation for several parameters.
Summary
This compilation demonstrates the efficacy and tolerability of topical applications of the medicinal plant Symphytum officinale, comfrey, also known as comfrey. For the treatment of blunt traumas, such as sprains, of myalgias, and especially of arthroses – such as osteoarthritis of the knee joint – Symphytum preparations are ideally suited and, depending on the evaluation, are not inferior or even superior to topical diclofenac applications. Within a week comfrey is able to very significantly reduce the discomfort such as tenderness, restricted movement, swelling, etc.. The medicinal plant is very well tolerated and can be used even in children.
It is thus recommended as an alternative to conservative treatments for corresponding injuries and complaints.
Literature:
- Andres P, et al: Relating antiphlogistic efficacy of dermatics containing extracts of Symphytum officinale to chemical profiles. Planta Medica 1989; 55: 66-67.
- Koll R, et al: Efficacy and tolerability of comfrey root extract (Extr. Rad. Symphyti) in ankle sprains. Results of a multicenter, randomized, placebo-controlled double-blind study. Z Phytother 2000; 21: 27-34.
- Grube B, et al: Efficacy of a comfrey root (Symphyti offic. Radix) extract ointment in the treatment of patients with painfull osteoathritis of the knee: results of a double-blind, randomised, bicenter, placebo-controlled trial. Phytomedicine 2007; 14: 2-10.
- Predel HG, et al: Efficacy of a comfrey root extract ointment in comparison to a diclofenac gel in treatment of ankle distorsions: results of an observer-blind, randomized, multicenter study. Phytomedicine 2005; 12: 707-714.
- Giannetti BM, et al: Efficacy and safety of a comfrey root extract intment in the treatment af acute upper or lower back pain: results of a double-blind, randomised, placebo-controlleds, multicenter trial. Br J Sport Med 2010; 33: 637-641.
- Koll R, et al: Efficacy and tolerance of a comfrey root extract (Extr. Rad. Symphyti) in the treatment of ankle distorsions: results of a randomized, multicenter, placebo-controlled, double-blind study. Phytomedicine 2004; 11: 470-477.
- Kucera M, et al: Topical symphytum herb concentrate cream against myalgia. Adv Ther 2005; 22: 681-692.
- Grünwald J, et al: Use and tolerability of comfrey cream (Symphyti herba) in children with acute blunt trauma. Z Phytother 2010; 31: 61-65.
- D’Anchise R, et al: Comfrex extract ointment in comparison to a diclofenac gel in the treatment of acute unilateral ankle sprains (distorsions). Drug Res 2007; 57: 712-716.
HAUSARZT PRAXIS 2017; 12(10): 2-3
