Cüneyt Çirak

Variation of bioactive secondary metabolites in Hypericum origanifolium during its phenological cycle

The genus Hypericum has received considerable interest from scientists, as it contains the variety of structurally diverse natural products which possess a wide array of biological properties. The present study was conducted to determine ontogenetic and morphogenetic variation of hypericin, chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin and quercetin content in Hypericum origanifolium growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Hypericin, quercetin and quercitrin content in whole plant increased during course of ontogenesis and the highest level was reached in blooming stage. On the contrary, hyperoside content of whole plant decreased linearly with advancing of development stages and the highest level was observed at vegetative stage. Plants produced similar amount of chlorogenic acid at all stages of plant phenology except for mature fruiting at which the amount of this compound was decreased sharply. Among different tissues, reproductive parts accumulated the highest level of hypericin, quercetin and quercitrin, however, leaves produced substantially higher amount of chlorogenic acid and hyperoside. Rutin and apigenin-7-O-glucoside were detectable in all tissues only during fruit maturation. The presence and variation of these bioactive substances in H. origanifolium were reported for the first time.

Essential oil composition and variability of Hypericum perforatum from wild populations of northern Turkey.

Context: Hypericum perforatum L. (Guttiferae) contains many bioactive secondary metabolites including hypericins, hyperforins, and essential oil. Objective: The present study was conducted to determine the variation in composition of essential oil in H. perforatum accessions from Turkey. Material and methods: At full flowering, aerial parts of 30 plants were collected from 10 sites of northern Turkey and assayed for essential oil components by GC-FID and GC-MS. Results: The chemical analysis revealed that the main constituents of the all analyzed samples were hydrocarbon and oxygenated sesquiterpenes such as β-caryophyllene (4.08–5.93%), γ-muurolene (5.00–9.56%), β-selinene (5.08–19.63%), α-selinene (4.12–10.42%), d-cadinene (3.02–4.94%), spathulenol (2.34–5.14%), and caryophyllene oxide (6.01–12.18%). Monoterpenes, both hydrocarbon and oxygenated, were represented by scarce amounts of α- and β-pinene, myrcene, linalool, cis- and trans-linalool oxide, and α-terpineol. Principal component analysis was also carried out and, according to the results, the first nine principal components were found to represent 100% of the observed variation. Discussion: The chemical variation among the populations is discussed as the possible result of different genetic and environmental factors. Conclusions: The wild populations examined here are potentially important sources for breeding and improvement of the cultivated varieties.

Variations in total phenolics during ontogenetic, morphogenetic, and diurnal cycles inHypericum species from Turkey

Several species ofHypericum are used in traditional Turkish folk medicine. Their most medicinally important secondary metabolites are the hypericins, hyperforins, and phenolics. Here, we determined the ontogenetic, morphogenetic, and diurnal variations in total phenolics contents fromH. aviculariifolium subsp.depilatum var.depilatum (endemic),H. perforation, andH. pruinatum. Plants of wild-growingH. aviculariifolium subsp.depilatum var.depilatum andH. perforatum, and greenhouse-grownH. pruinatum were harvested four times per day during their vegetative, floral-budding, full-flowering, fresh-fruiting, and mature-fruiting stages. They were then dissected into stem, leaf, and reproductive tissues to be dried separately and assayed. The highest level of phenolics inH. aviculariifolium subsp.depilatum var.depilatum andH. pruinatum was found in the leaves, whereas the floral buds produced the greatest amount inH. perforatum. Variations in contents from whole plants fluctuated diurnally, differing among species over the course of ontogenesis, reaching the highest level at floral-budding and tending to increase at mid-day inH. aviculariifolium subsp.depilatum var.depilatum. ForH. perforatum andH. pruinatum, contents also were the highest during floral development, although no diurnal fluctuations were observed in those species.

Hypericin and Pseudohypericin Contents in Some Hypericum. Species Growing in Turkey

Abstract Hypericin and pseudohypericin content in stems, leaves, and flowers of some Hypericum. species growing in Turkey, namely, H. heterophyllum. Vent, H. hyssopifolium. L., H. linarioides. Bosse, H. monbretii. Spach, H. orientale. L., H. origanifolium. Willd., H. perforatum. L., H. scabrum. L., and H. triquetrifolium. Turra, was determined by HPLC. Hypericin and pseudohypericin were detected in all species tested except for H. heterophyllum., and the presence in H. orientale. and H. scabrum. was reported by us for the first time in the current study. Hypericin and pseudohypericin contents observed in the study varied greatly depending on species and plant tissues. The lowest levels of hypericin and pseudohypericin were detected in leaves of H. hyssopifolium. [0.030 and 0.051 mg/g dry weight (DW), respectively] whereas flowers of H. montbretii. produced the highest levels of both hypericin forms (2.52 mg/g DW hypericin and 3.58 mg/g DW pseudohypericin). H. montbretti. and H. triquetrifolium. were found to be superior over H. perforatum. with regard to hypericin and pseudohypericin content, encouraging the cultivation and biological evaluation of these species in Turkey.

Variation of bioactive substances in Hypericum montbretii during plant growth

The present study was conducted to determine phenologic and morphogenetic variation of chlorogenic acid and flavonoids, as rutin, hyperoside, apigenin-7-O-glucoside, quercitrin, quercetin and viteksin content of Hypericum montbretii growing in Turkey. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for bioactive compounds by HPLC method. Accumulation of rutin and quercetin was not detected in plant parts of H. montbretii during plant growth. Chlorogenic acid and hyperoside content in whole plant was decreased linearly with advancing of development stages and reached their highest level at vegetative stage. On the contrary, apigenin-7-O-glucoside, quercitrin and viteksin content in whole plant increased during the course of seasonal development and the highest level of those compounds was observed at the stage of full flowering. Leaves did not produce apigenin-7-O-glucoside, while viteksin was not detectable in stem and reproductive tissues. Depending on development stages, reproductive parts had the highest level of apigenin-7-O-glucoside and leaves produced major amount of chlorogenic acid, hyperoside and viteksin whereas accumulation of quercitrin was prevailed in stem tissue. Such kind of data could be useful for elucidation of the chemotaxonomical significance of these compounds and medicinal evaluation of this species.

Variation of hypericins in Hypericum triquetrifolium Turra growing in different locations of Turkey during plant growth

The principle medicinal secondary metabolites present in Hypericum species are thought to be naphthodianthrones hypericin and pseudohypericin. The present study was conducted to determine ontogenetic and morphogenetic variations of hypericin and pseudohypericin contents in Hypericum triquetrifolium growing in two sites located in Northern Turkey. Plants were harvested at vegetative, flowering and fructification stages. Plants were dissected into stem, leaf and reproductive tissues at the time of harvest, dried separately and assayed for hypericin and pseudohypericin contents by high-performance liquid chromatography. The hypericin and pseudohypericin concentrations in the leaves and reproductive parts were highest at flowering and fructification, whereas the stem contents of these compounds decreased with advancing plant growth in both sites. The leaves contained higher concentrations of both naphthodianthrones than the stems or reproductive parts of H. triquetrifolium.

Variation of hyperforin in Hypericum montbretii during its phenological cycle

Hypericum montbretii, a perennial herbaceous plant from Turkish flora has a great pharmaceutical potential with its well-documented chemical content. In the present study, morphogenetic and phenological variations of hyperforin were investigated in this species for the first time. Wild growing plants were harvested at vegetative, floral budding, full flowering, fresh fruiting, and mature fruiting stages and dissected into stem, leaf and reproductive tissues and assayed for hyperforin by HPLC method. Phenological changes in hyperforin content were found to be significant. After decreasing at floral budding slightly, hyperforin concentration in whole shoots increased with advancing of plant development and the highest level was reached at fresh fruiting. Among different parts of the plant, reproductive tissues namely green capsules and full opened flowers accumulated significantly higher amount of hyperforin when compared to stems and leaves. Such kind of data could be useful for elucidation of the chemotaxonomical significance of hyperforin and phytochemical evaluation of H. montbretii.

Morphogenetic changes in essential oil composition of Hypericum perforatum during the course of ontogenesis.

Context: In the past few years, an increasing interest in the volatile secondary metabolites of Hypericum perforatum L. (Guttiferae) has been arising. Objective: The present study is a contribution to better understand the relationship between the morphological variations and volatile composition during the phenological cycle. Materials and methods: Leaves at the stages of vegetative, floral budding, flowering and green capsule, buds, full opened flowers and green capsules were assayed for essential oil (EO) components by gas chromatography-flame ionization detector (GC-FID) and GC-mass spectrometry (MS). Results: Significant amounts of sesquiterpenes (oxygenated 26–50% and hydrocarbons 20–40%) and oxygenated hydrocarbons (13–38%) characterized the all analyzed samples showing peculiar fluctuations during the seven phenological stages. Although monoterpenes were present in much lower amounts (monoterpene hydrocarbons 0.4–6%; oxygenated monoterpenes 0.8–6%) they were considered also important discrimination for several stages. The green capsules and the full opened flowers collected at flowering stage were clearly distinguished in terms of EO compositions from the other samples. Discussion: For the first time, the EO composition of Turkish wild Hypericum perforatum was monitored by the hydrodistillation of different plant organs collected at different seven stages in order to point out the modification of target volatiles related to each phenological step. Conclusions: Based on the EO composition monitored during these seven morphological stages by GC-MS, principal component analysis and cluster analysis, significant metabolite modifications were observed during the phenological cycle which involved the levels of specific volatile target compounds belonging to the chemical classes of hydrocarbons, monoterpenes and sesquiterpenes.

Chemical constituents of Hypericum adenotrichum Spach, an endemic Turkish species

The present study was conducted out to determine hyperforin, hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, quercitrin, quercetin, kaempferol, apigenin-7-O-glucoside and amentoflavone contents of Hypericum adenotrichum, an endemic plant species to Turkey. The aerial parts representing a total of 30 individuals were collected at full flowering, dried at room temperature and assayed for secondary metabolite concentrations by HPLC. All of the chemicals were detected at various levels except for hyperforin. This is the first report on polar chemistry of this endemic species.

Direct and indirect regeneration of plants from internodal and leaf expiants ofHypencum bupleuroides gris

Species of the genusHypencum are of considerable interest worldwide because of their medicinal properties.In- vitro culture is a useful tool for both multiplication of the genus and studying its economically important secondary metabolites. Here, we present an effectivein- vitro propagation method forH. bupleuroides. Leaf and internodal expiants excised from 9-week-old,in vitro-germinated seedlings were cultured on a Murashige and Skoog (MS) medium supplemented with benzyladenine (BA; 1.0 or 0.1 mg L-1) and 2,4-dichlorophenoxyacetic acid (2,4-D; 1.0 or 0.1 mg L1). Depending on the BA and 2,4-D combination used, these cultures produced adventitious shoot buds directly on the surfaces of both types of explants as well as excessive calli. Numerous shoots were obtained when the calli from both expiant types were cultured on an MS medium supplemented with 2 mg L-1 BA. Internodal expiants were more responsive than leaf tissues to direct and indirect plant regeneration. After shoots that regenerated from either the calli or the expiant surface were excised, rooting was best on an MS medium lacking any growth hormones. These rooted plants were then acclimatized under greenhouse conditions, and 90% of regenerants had survived. Ours is the first report ofin- vitro plant regeneration fromH. bupleuroides.