No abstract

The genus Marrubium (Lamiaceae) is comprised of about forty species, distributed in Europe, Asia and Brazil. Some species are traditionally used to treat various diseases, including asthma, pulmonary infections, inflammation and hypotension, as cholagogues and sedative agents, and for pain relief. A literature review on the chemical and biological aspects of these plants indicates antimicrobial activity against gram positive bacteria, analgesic properties, and anti-hypertensive, antidiabetic, antioxidant properties, among others, particularly related to the presence of diterpenes, sterols, phenylpropanoids and flavonoids. This review shows the main chemical and pharmacological aspects of the genus Marrubium, with emphasis on M. vulgare, which grows in Brazil and has been studied by us and other authors.

The results, including the inhibition of mediators (BK, NO, SP, PGE(2) and TNF-á) and enzyme (MPO and ADA) activity, validate the use of the plant under study for therapeutic treatment of anti-inflammatory, painful and wound healing processes.

Seeking to develop a new analgesic phytomedicine, a spray-dried extract (SDE) of Aleurites moluccana (L.) Willd. leaves was developed in scale up (5 kg). The SDE was standardized at 3% w/w in relation to the flavonoid 2′′-O-rhamnosylswertisin. The SDE batches were evaluated in relation to their physical, physiochemical, and pharmacological characteristics. The results demonstrated the reproducibility of the scale up SDE process which, when dosed orally, reduced carrageenan-induced mechanical hypernociception, with an ID50% of 443 mg/kg. Similar results were obtained with animals injected with complete Freund's adjuvant (CFA), in which SDE caused inhibition of 48 ± 4%. SDE was effective in preventing prostaglandin E2 (PGE2)-induced mechanical hypernociception (inhibition of 26 ± 10% and 33 ± 3%, at 250 and 500 mg/kg, respectively). Swertisin and 2′′-O-rhamnosylswertisin isolated from the own extract were effective in inhibiting the hypernociceptive response induced by carrageenan (70 ± 2% and 50 ± 5%, resp.). Furthermore, 2′′-O-rhamnosylswertisin was capable of significantly inhibiting the mechanical sensitization induced by CFA or PGE2, with inhibitions of 25 ± 3% and 94 ± 6%, respectively. These results suggest that the effects of SDE are related, at least in part, to the presence of these flavonoids.

This study examined the antinociceptive effect of Bauhinia microstachya (Leguminosae), a native plant widely distributed in the South of Brazil, in several chemical and mechanical models of pain. The methanolic extract (ME) from B. microstachya (3--30 mg kg(-1), i.p.) and the isolated compound quercitrin (1--10 mg kg(-1), i.p.), given 30 min earlier, produced a dose-dependent inhibition of acetic-acid-induced visceral pain in mice, with a mean ID50 value (dose necessary to reduce the nociceptive response by 50% relative to the control value) of 7.9 and 2.4 mg kg(-1), respectively. The ME of B. microstachya (3--100 mg kg(-1), i.p., 30 min earlier) also caused a dose-dependent inhibition of capsaicin-induced pain, with a mean ID50 value of 18.8 mg kg(-1). Moreover, the ME (3--100 mg kg(-1), i.p., 30 min earlier) produced marked inhibition of both phases of formalin-induced pain, with mean ID50 values for the neurogenic and the inflammatory phases of 30.3 and 17.2 mg kg(-1), respectively. In addition, the ME of B. microstachya (3--300 mg kg(-1), i.p., 30 min earlier) inhibited, in a graded manner, the hyperalgesia induced by bradykinin (3.2 microg/paw), substance P (13.5 microg/paw), carrageenan (300 microg/paw), capsaicin (100 microg/paw) and adrenaline (100 ng/paw) in the rat paw, with mean ID50 values of 20.5, 17.9, 101.8, 54.2 and 99.7 mg kg(-1), respectively. Taken together, these data demonstrate that ME of B. microstachya elicited a pronounced antinociceptive action against several chemical and mechanical models of pain in mice and rats. The precise mechanism responsible for the antinociceptive effect of the extract still remains unclear, but seems to be partly related to modulation of the release or action of pro-inflammatory mediators involved in the models of pain used. Finally, the flavonoid quercitrin isolated from this plant appears to contribute for the antinociceptive property of the methanolic extract.