A New Pregnane and a New Diphenylmethane from the Root Barks ofPeriploca sepium

Genus Periploca (Apocynaceae): A Review of Its Classification, Phytochemistry, Biological Activities and Toxicology

The genus Periploca belongs to the family Apocynaceae, which is composed of approximately ten species of plants according to incomplete statistics. Most of these plants serve as folk medicines with a long history, especially Periploca sepium and Periploca forrestii. The botanical classifications, chemical constituents, biological activities and toxicities of the genus Periploca were summarized in the literature from 1897 to early 2019. Though the botanical classification of this genus is controversial, these species are well-known to be rich sources of diverse and complex natural products-above all, cardiac steroids and C₂₁ pregnane steroids with special structures and obvious pharmacological activities. The various crude extracts and 314 isolated metabolites from this genus have attracted much attention in intensive biological studies, indicating that they are equipped with cardiotonic, anti-inflammatory, immunosuppressive, antitumor, antimicrobial, antioxidant, insecticidal and other properties. It is noteworthy that some cardiac glycosides showed hepatotoxicity and cardiotoxicity at certain doses. Therefore, in view of the medical and agricultural value of the genus Periploca, in-depth investigations of the pharmacology in vivo, the mechanisms of biological actions, and the pharmacokinetics of the active ingredients should be carried out in the future. Moreover, in order to ensure the safety of clinical medication, the potential toxicities of cardiac glycosides or other compounds should also be paid attention. This systematic review provides an important reference base for applied research on pharmaceuticals and pesticides from this genus.

Effects of periplocoside X on midgut cells and digestive enzymes activity of the soldiers of red imported fire ant

The pathological effects of ingested periplocoside X, an insecticidal component isolated from the root of Periploca sepium Bunge, on the midgut epithelial cells of the soldiers of red imported fire ant were studied and the symptom was described. The results showed that periplocoside X could induce a severe, time-dependent cytotoxicity in the midgut epithelial cells. An optical microscopy showed that epithelial cells swelled firstly and then lysed. Transmission electron microscopy (TEM) showed that numerous swollen lysosomes were appeared, microvilli were disrupted and sloughed off, and the numbers of the rough endoplasmic reticulum and the mitochondria decreased sharply in earlier stage. Numerous vacuoles were observed in the later stage. Finally, periplocoside X resulted in cell death by cytolysis. Assay of main three digestive enzymes activity indicated that amylase activity was significantly inhibited, but no significant changes were seen for lipase activity and total protease activity. So it is suggested that periplocoside X induced mainly to organic damage of midgut epithelium cells of insect. In all, insect midgut is one of targets for periplocoside X.

Five new C21 steroidal glycosides from Periploca sepium

Five new C(21) steroidal glycosides, named periseosides A-E (1-5), along with six known analogues, were isolated from the root barks of Periploca sepium. Their structures were elucidated on the basis of spectroscopic analysis and chemical evidence. All compounds were evaluated for their immunosuppressive activities.

Immunosuppressive pregnane glycosides from Periploca sepium and Periploca forrestii

Nine pregnane glycosides containing peroxy functions in their sugar moieties (1-5 and 11-14), five oligosaccharides (6-10), six pregnane glycosides (15-20), and five cardiac glycosides (21-25) were isolated from the root barks of Periploca sepium Bge. (Asclepiadaceae) and the roots of Periploca forrestii Schltr. (Asclepiadaceae), two traditional Chinese medicines used for the treatment of rheumatoid arthritis. Among them, 1-8 are hitherto unknown. Their structures were characterized on the basis of spectroscopic analyses. In pharmacological testing, compounds 1-5 and 11-14 were found to exhibit inhibitory activity against the proliferation of T lymphocyte in vitro with IC50 values ranging from 0.29microM to 1.97microM, while the other components showed no significant inhibitory activity.