Antiviral triterpenoids from the medicinal plant Schefflera heptaphylla

Abstract

Schefflera heptaphylla (L.) Frodin is a principal ingredient of an herbal tea formulation widely used for the treatment of common cold in southern China. An extract of the long leafstalk of the compound leaf of S. heptaphylla exhibited the most potent antiviral activity against respiratory syncytial virus (RSV). Further antiviral-guided fractionation and isolation of the leafstalk extract of S. heptaphylla led to obtain two highly active pure triterpenoids, namely 3alpha-hydroxylup-20(29)-ene-23,28-dioic acid and 3-epi-betulinic acid 3-O-sulfate, together with an inactive saponin, 3alpha-hydroxylup-20(29)-ene-23,28-dioic acid 28-O-alpha-l-rhamnopyranosyl-(1-->4)-O-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside. An antiviral assay using a cytopathic effect (CPE) reduction method showed that the two triterpenoids possessed broader antiviral activity against respiratory syncytial virus (RSV) with a similar 50% inhibition concentration (IC(50)) value of 6.25 microg/mL, influenza A (H1N1) virus with IC(50) values of 25 and 31.3 microg/mL, Coxsackie B3 (Cox B3) virus with IC(50) values of 12.5 and 20 microg/mL and herpes simplex virus type 1 (HSV-1) with IC(50) values of 18.8 and 25 microg/mL, respectively, whereas the saponin did not have antiviral activity against these four viruses at a concentration of 100 microg/mL.

Sterols and Triterpenoids with Antiviral Activity

“…Oleanolic acid (13) was identified as an anti-HIV principle from several plants, including Rosa woodsii (leaves), Prosopis glandulosa (leaves and twigs), Phoradendron juniperinum (whole plant), Syzygium claviflorum (leaves), Hyptis capitata (whole plant) and Ternstromia gymnanthera (aerial part). It inhibited HIV-1 replication in acutely infected H9 cells with an EC 50 value of 1.7 μg/mL and inhibited H9 cell growth with an IC 50 value of 21.8 g/mL (TI 12.8) [15].…”

“…Frodin is a principal ingredient of an herbal tea (Schefflera heptaphylla) formulation widely used for the treatment of common cold in southern China [13]. An extract of the long leafstalk of the compound leaf of S. heptaphylla exhibited the most potent antiviral activity against respiratory syncytial virus.…”

“…Nine triterpenes were characterized as oleanolic acid (13), ursolic acid (18), maslinic acid (19), 2 -hydoxyursolic acid (36), tormentic acid (37), 2 ,19 -dihydroxy-3-oxo-urs-12-en-28-oic acid (38), hyptadienic acid (39) and a mixture of 3-O-cis-p-coumaroyltormentic acid (40) and 3-O-trans-pcoumaroyltormentic acid (41). The triterpene composition in the callus tissues was noticeably different from that in intact leaves.…”

Levels of Antiviral Therapy

“…Another equally interesting group of chemical compounds that suppress the adsorption of viruses can be called triterpene saponins and steroids. These compounds are capable of changing the spatial structure of the cell membrane because of its structural features by binding with membrane cholesterol [15,16].…”

Antiviral activity of carnosic acid against respiratory syncytial virus

“…Thus, there is an urgent need for the development of effective and safe vaccines and therapeutics. Previous studies showed inhibition of hRSV by several natural compounds, including amentoflavone [9]; anagyrine, oxymatrine, sophoranol, wogonin, and oroxylin A [10]; 3-alpha-hydroxy-lup-20(2 9)-ene-23,28-dioic acid and 3-epi-betulinic acid 3-O-sulfate [11]; and cimicifugin [12]. …”