Lowering the Intraocular Pressure in Rats and Rabbits by Cordyceps cicadae Extract and Its Active Compounds.

Li-Ya Lee,Chin-Chu Chen,Hsin-I Fu,Jui-Hsia Hsu,Kwong-Chung Tung

doi:10.3390/molecules27030707

Abstract

Cordyceps cicadae (CC), an entomogenous fungus that has been reported to have therapeutic glaucoma, is a major cause of blindness worldwide and is characterized by progressive retinal ganglion cell (RGC) death, mostly due to elevated intraocular pressure (IOP). Here, an ethanolic extract of C. cicadae mycelium (CCME), a traditional medicinal mushroom, was studied for its potential in lowering IOP in rat and rabbit models. Data showed that CCME could significantly (60.5%) reduce the IOP induced by microbead occlusion after 56 days of oral administration. The apoptosis of retinal ganglion cells (RGCs) in rats decreased by 77.2%. CCME was also shown to lower the IOP of normal and dextrose-infusion-induced rabbits within 60 min after oral feeding. There were dose effects, and the effect was repeatable. The active ingredient, N6-(2-hydroxyethyl)-adenosine (HEA), was also shown to alleviate 29.6% IOP at 0.2 mg/kg body weight in this rabbit model. CCME was confirmed with only minor inhibition in the phosphorylated myosin light chain 2 (pMLC2) pathway.

Highlights

C. cicada is an entomopathogenic fungus that produces fruit on the head of the host (Cicada flammata) and forms a fruiting body on the surface of the insect
C. cicadae (BCRC MU 30106) deposited in Bioresources Collection and Research Center (BCRC) in Food Industry Research and Development Institute (Hsinchu, Taiwan) was incubated in a medium composed of 2% glucose, 1% yeast extract, and 1% soybean powder adjusted to pH 6.0 at 25 ◦ C on a rotary shaker (120 rpm) for 3 days
A 10 uL magnetic microbeads suspension was injected into anterior chambers of the right eye to block the outflow of the aqueous humor (AH) at day 0 (Figure 1)

Summary

Introduction

C. cicada is an entomopathogenic fungus that produces fruit on the head of the host (Cicada flammata) and forms a fruiting body on the surface of the insect. The hybrid of fruiting body and insect has been used as traditional Chinese medicine for 1600 years. It possesses many medical effects similar to Hirsutella sinensis such as antioxidation [1,2], anti-inflammation [3,4], lowering blood sugar [5], and renal protection [6,7]. Zheng’s findings indicated that HEA, an active compound from C. cicadae, has a beneficial effect on UUO-induced tubulointerstitial fibrosis by suppressing inflammation and renal fibroblast activation. Treatment with HEA (20 and 40 mg/kg) for six weeks reduced blood glucose in alloxan-induced diabetic rats [9]. The safety of C. cicadae mycelium has been evaluated in rat, rabbit, pig, and mouse models, as well as humans [10,11,12,13,14,15,16,17,18,19]

Methods

Discussion

Conclusion