Plectranthus Species with Anti-Inflammatory and Analgesic Potential: A Systematic Review on Ethnobotanical and Pharmacological Findings

The use of medicinal plants to treat inflammatory conditions and painful processes has attracted the attention of scientists and health professionals due to the evidence that natural products can promote significant therapeutic benefits associated with fewer adverse effects compared to conventional anti-inflammatory drugs. The genus Plectranthus is composed of various plants with pharmacological potential, which are used to treat various diseases in traditional communities worldwide. The present study systematically reviewed Plectranthus species with anti-inflammatory and analgesic potential. To this end, a systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The search was conducted on the following databases: PubMed, ScienceDirect, SciVerse Scopus, and Web of Science. Different combinations of search terms were used to ensure more excellent article coverage. After the selection, a total of 45 articles were included in this review. This study identified twelve Plectranthus species indicated for the treatment of different inflammatory conditions, such as wounds, fever, bronchitis, abscess, asthma, hepatitis, labyrinthitis, tonsillitis, and uterine inflammation. The indications for pain conditions included headache, sore throat, heartburn, menstrual cramp, colic, toothache, stomachache, migraine, chest pain, abdominal pain, local pain, labor pain, and recurring pain. Among the listed species, ten plants were found to be used according to traditional knowledge, although only four of them have been experimentally studied. When assessing the methodological quality of preclinical in vivo assays, most items presented a risk of bias. The SR results revealed the existence of different Plectranthus species used to treat inflammation and pain. The results of this systematic review indicate that Plectranthus species have the potential to be used in the treatment of diseases with an inflammatory component, as well as in the management of pain. However, given the risk of biases, the experimental analysis of these species through preclinical testing is crucial for their safe and effective use.

GC-MS characterisation and biological activity of essential oils from different vegetative organs of Plectranthus barbatus and Plectranthus caninus cultivated in north Italy

Essential oils (EOs) from the roots, stems and leaves of Plectranthus barbatus (A) and Plectranthus caninus (B), cultivated in north Italy, were obtained by steam distillation and chemically characterised by gas chromatography-mass spectrometry. The highest yields were obtained from roots (268.15 and 673.60 mg/kg from A and B), followed by leaves (64.34 and 26.65 mg/kg) and stems (19.76 and 18.63 mg/kg). A total of 128 structures were identified in A and 121 in B. Fe(++) chelating and antiradical activities (DPPH and ABTS) were evaluated: root and stem EOs showed the strongest activities, while EOs from leaves did not show relevant activities. All EOs were tested for their in vitro antimicrobial activity, showing optimal growth-inhibition in antibiogram (∅>35 mm) and MIC tests (32-64 μg/mL) against Candida albicans, while EOs from leaves of both species showed a good activity (25 < ∅ < 34 mm, MIC 64-128 μg/mL) against Escherichia coli.