# Plant Iridoids Affect Intraocular Pressure and Vascular Flow in the Rabbit Eye
## 4 Discussion
found that within 5 months, _Ginkgo biloba_ extract administered orally decreased IOP by 29.8% in rats with chronic elevated intraocular pressure [25]. The authors also observed positive changes in retinal ganglion cell loss in the investigated group. [PERSON] et al. noticed that patients with primary open-angle glaucoma and IOPs ranging between 15 and 23 mmHg who were treated with 120 mg of ginkgo biloba extract at 30 months achieved a significant decrease in this value [26]. On the other hand, it was shown that oral _Gingko biloba_ extract has no impact on IOP in consecutive patients with newly-diagnosed NTG [27]. Orally administered extract of _Cordycey cicadae_, an entomogenous fungus, containing N6-(2 hydroxyethyl)-adenosine as a bioactive compound, significantly (60.5%) reduced IOP at a dose of 0.2 mg/kg b.w, after 56 days [28]. High extracts of pine bark and bilberry fruits decreased IOP in Japanese subjects with primary open-angle glaucoma after 4 weeks of administration at 130 mg per day [29]. Catalpol has a positive effect on atherosclerotic lesions in rabbits with alkoxan-induced diabetes. The possible mechanisms may be related to the inhibition of the inflammatory response after oxidative stress and antifibrosis, as well as to the extracellular matrix. Catalpol administration alleviated diabetic atherosclerosis in diabetic rabbits, as demonstrated by the significant inhibition of neointima hypertrophy and macrophage recruitment. Therapy increased the superoxide dismutase activity, glutathione peroxidase, and plasma levels of total antioxidant status, while reducing the levels of malondialdehydedehyde, protein carbonyl groups, and the advanced glycation end product. Cat also reduced the levels of tumor necrosis factor-\(\alpha\) in the circulation, monocyte chemotactic protein-1, and vascular cell adhesion molecule-1a, and it also reduced the expression of mRNA and transforming growth factor-\(\beta\)1 and collagen IV in the vessels [30] Catalpol was able to reduce LPS (Escherichia coli serotype O55:B5)-induced microvascular barrier damage and hemorrhage in the mesenteric circulation by targeting both TLR-4 and Src, thus attenuating the phosphorylation of Src kinase, phosphatidylinositol 3-phosphatidyl kinase, and focal kinase, as well as cathepsin B activation [31]. Catalpol and Puerrin are two monomers of _Rehmannia glutinosa_ and _lobed kudzuvine_ root, which are herbs commonly used together in ancient prescriptions of traditional Chinese medicine for cerebral ischemia [32]. [PERSON] et al. investigated the effects of freeze-dried Catal powder and Puerrin on cerebral ischemia in rats. They found an increase in regional cerebral blood flow, a reduced infarct volume, protection of vascular integrity, and inhibition of endothelial cell apoptosis in vivo. In a rat model of stroke after occlusion of the right middle cerebral artery, catalpol was found to affect neuroprotection and angiogenesis through the JAK2/STAT3 signaling pathway, mediated by STAT3 activation and VEGF expression. Catalpol may be used as a potential treatment for stroke [33]. Catalpol exhibited potent neuroprotective effects in mice after experimental autoimmune encephalomyelitisitis. Cat also plays a role in remyelination by promoting the expression of the transcription factors Olig1 and Olig2 [34]. Catalpol and geniposide, as two types of iridoid glycosides with high activity, are the main bioactive components of _Rehmannia glutinosa_ and _Gardenia jasminoides_ Ellis, respectively. Preclinical experiments have shown that they have significant neuroprotective effects against Alzheimer's disease, Parkinson's disease, stroke, and depression [35]. Catalpol, the main active component of the roots of _Rehmannia glutinosa_, can reduce liver damage in a mouse model of cholestasis by inhibiting oxidative stress and enhancing the potential of the mitochondrial membrane.