Discovery of antifungal constituents from the Miao medicinal plant Isodon flavidus

Abstract

Our identification of two antifungal compounds provided strong evidence for the Miao people to use I. flavidus as a medicinal plant for treatment of athlete's foot disease. The very different chemical structures of the active compounds from those in the market presents them as potential antifungal lead compounds for follow-up study.

3,4-Seco-Isopimarane Diterpenes from the Twigs and Leaves of Isodon Flavidus

“…Hypothetically, they might be derived from isopimarane diterpenes, which are found abundantly in Isodon plants [ 11 , 12 ]. The original precursor of the diversified isopimarane-type diterpenes in Isodon plants could well be 3 β -hydroxy-8,15-isopimaradiene ( 4 ), a rich isopimarane diterpenoid observed in several Isodon plants [ 10 ]. Given that background, a plausible biogenetic pathway of 1 – 3 originating from the natural precursor ( 4 ) is proposed ( Scheme 1 ) [ 10 , 25 , 26 ].…”

“…The 3,4- Seco -isopimarane diterpenes belong to isopimaranes with the rearrangement of ring A by the bond break between C-3 and C-4. To date, there have been few reports on natural 3,4- seco -isopimaranes [ 9 , 10 ], and no antiviral activity has been reported for this type of compound.…”

“…Diterpenoids with a tricyclic core system and their seco -derivatives were also reported from this genus, including I. rubescens , I. lophanthoides , and I. flavidus [ 15 , 16 , 17 , 18 ]. I. flavidus is a commonly used herb to defend against tinea pedis by the Miao minority in China [ 10 ]. Phytochemical investigation of this plant revealed the presence of isopirmarane [ 19 , 20 ] and ent -kaurane diterpenoids [ 15 ], along with other types of compounds such as flavonoids and steroids [ 19 , 20 ].…”

“…In our previous study, two antifungal constituents, fladin A and lophanic acid, were isolated and identified from this plant. Fladin A was a 3,4- seco -isopimarane diterpenoid, and lophanic acid was an abietane diterpenoid [ 10 ]. In a search for novel bioactive compounds from I. flavidus , we further obtained three new diterpenes, namely fladins B ( 1 ), C ( 2 ), and D ( 3 ).…”

Antimicrobial activities and preliminary phytochemical tests of crude extracts of important ethnopharmacological plants from Brazilian Cerrado

“…The use of plants with therapeutic properties is an ancient practice and plants has been used as an important source of bioactive compounds (Pinto et al, 2002;Ncube et al, 2012;Khan et al, 2013;Li et al, 2016). Eating herbs and leaves to relieve and to cure diseases was the earliest methodologies involving natural products (Viegas et al, 2006).…”