Reassessment of Melittis melissophyllum L. subsp. melissophyllum iridoidic fraction

Phytochemical analysis on the aerial parts of Teucrium capitatum L. with aspects of chemosystematics and ethnobotany

The phytochemical analysis on the aerial parts of Teucrium capitatum L. collected from a new population in Central Italy, led to the identification of eight compounds, i.e. pheophytin a (1), poliumoside (2), apigenin (3), luteolin (4), cirsimaritin (5), cirsiliol (6), 8-O-acetyl-harpagide (7) and teucardoside (8) belonging to four different classes of secondary metabolites. Pheophytin a (1) represents a newly identified compound in the genus whereas compounds (7-8) are newly identified compound in the species. The chemotaxonomic and ethnobotanical aspects relative to the presence of these compounds were widely discussed suggesting important conclusions for both.

An overview of the genus Aloysia Paláu (Verbenaceae): Essential oil composition, ethnobotany and biological activities

Aloysia Paláu is an important herbal genus from the Verbenaceae family and possesses numerous remedial properties in the folk medicine of Asian, European, and, in particular, South American countries. Only a few reports have discussed some phytochemical characteristics associated with Aloysia species. Right the lack of an exhaustive report prompted us to organize this review article. Accordingly, besides the ethnobotanical knowledge of Aloysia species, their essential oil profiles, phytochemistry of the polar isolated fractions, and the relevant biological activities are discussed in detail.

Bio-Guided Investigation of Sideritis cypria Methanol Extract Driven by in Vitro Antioxidant and Cytotoxic Assays

Sideritis cypria Post is an endemic and endangered species of Northern Cyprus. The overall aim of the present study was to evaluate the total phenolic content, the antioxidant, the cytotoxic and the antimicrobial activity of the methanol extract obtained from the aerial parts of cultivated S. cypria. A bio-guided approach led to the isolation of 27 chemical compounds by using various analytical techniques. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopy. The crude extract exerted strong antioxidant activity (DPPH and FRAP assays) which was attributed to its high total phenolic content. Furthermore, groups rich in phenolic content showed highest antioxidant property, whereas groups with phytosterols, diterpenoids and apigenin derivatives exerted cytotoxic effects in MDA-MB231 cancer cell line by the MTT method. Moreover, the cytotoxic activity of four isolated apigenin derivatives was evaluated in the same cancer cells. The antimicrobial activity of the extract and groups were measured, demonstrating lack of activity. To the best of our knowledge, this survey is the first report on the biological activities of the methanol extract of S. cypria.

Harpagide: Occurrence in plants and biological activities - A review

In this review article, the occurrence of harpagide in the plant kingdom and its associated biological activities are presented and detailed for the first time. The presence of harpagide has been reported in several botanical families within Asteridae, and harpagide has been observed to exert a wide number of biological activities such as cytotoxic, anti-inflammatory, and neuroprotective. These results show how harpagide can be recovered from several natural sources for several pharmacological purposes even if there is a lot to still be studied. Nowadays, the interest is related to its presence in phytomedicines. Threfore, these studies are useful to support and validate the large use of several plants in the folklore medicine.

Enhanced accumulation of harpagide and 8-O-acetyl-harpagide in Melittis melissophyllum L. agitated shoot cultures analyzed by UPLC-MS/MS

Harpagide and its derivatives have valuable medicinal properties, such as anti-inflammatory, analgesic and potential antirheumatic effects. There is the demand for searching plant species containing these iridoids or developing biotechnological methods to obtain the compounds. The present study investigated the effects of methyl jasmonate (MeJa, 50 μM), ethephon (Eth, 50 μM) and L-phenylalanine (L-Phe, 2.4 g/L of medium), added to previously selected variant of Murashige and Skoog medium (supplemented with plant growth regulators: 6-benzylaminopurine 1.0 mg/L, α-naphthaleneacetic acid 0.5 mg/L, gibberellic acid 0.25 mg/L) on the accumulation of harpagide and 8-O-acetyl-harpagide in Melittis melissophyllum L. agitated shoot cultures. Plant material was harvested 2 and 8 days after the supplementation. Iridoids were quantitatively analyzed by the UPLC-MS/MS method in extracts from the biomass and the culture medium. It was found that all of the variants caused an increase in the accumulation of harpagide. In the biomass harvested after 2 days, the highest harpagide content of 247.3 mg/100 g DW was found for variant F (L-Phe and Eth), and the highest 8-O-acetyl-harpagide content of 138 mg/100 g DW for variant E (L-Phe and MeJa). After 8 days, in some variants, a portion of the metabolites was released into the culture medium. Considering the total amount of the compounds (in the biomass and medium), the highest accumulation of harpagide, amounting to 619 mg/100 g DW, was found in variant F, and the highest amount of 8-O-acetyl-harpagide, of 255.4 mg/100 g DW, was found in variant H (L-Phe, MeJa, Eth) when harvested on the 8th day. These amounts were, respectively, 24.7 and 4.8 times higher than in the control culture, and were, respectively, 15 and 6.7 times higher than in the leaves of the soil-grown plant. The total amount of the two iridoids was highest for variant F (0.78% DW) and variant H (0.68% DW) when harvested on the 8th day. The results indicate that the agitated shoot cultures of M. melissophyllum can be a rich source of harpagide and 8-O-acetyl-harpagide, having a potential practical application. To the best of our knowledge we present for the first time the results of the quantitative UPLC-MS/MS analysis of harpagide and 8-O-acetyl-harpagide in M. melissophyllum shoot cultures and the enhancement of their accumulation by means of medium supplementation with elicitors and precursor.

Reassessment of the polar fraction of Stachys alopecuros (L.) Benth. subsp. divulsa (Ten.) Grande (Lamiaceae) from the Monti Sibillini National Park: A potential source of bioactive compounds

BACKGROUND

The phytochemical analysis of Stachys alopecuros subsp. divulsa, an endemic Italian species, has been recently reported and has showed the presence of 8-O-acetylharpagide (2), harpagide (3), allobetonicoside (4), and 4¢-O-galactopyranosyl-teuhircoside (5). In this paper, an in deep study of its glycosidic fraction with the aim to widen the knowledge on its secondary metabolites content is reported.

MATERIALS AND METHODS

Chromatographic techniques were used for the isolation of constituents while spectroscopic and spectrometric techniques were applied for the structures elucidation.

RESULTS

Besides the known constituents, all of them reconfirmed, ajugoside (1), reptoside (6) and 6-O-acetyl-ajugol (7) were also identified among the iridoids while the phenolic components resulted to be chlorogenic acid (8), b-arbutin (9), verbascoside (10), and stachysoside A (11), instead.

CONCLUSION

The iridoid pattern of S. alopecuros subsp. divulsa has been expanded with the identification of not previously reported compounds as well as for the phenolic fraction. Except for the reconfirmed verbascoside (10), the other phenolic compounds were recognized for the first time in the studied species. The complete NMR assignment of compound (1) by means of bidimensional techniques is reported, and both the chemotaxonomic and pharmacological relevance of the isolated compounds is largely discussed.

Polar Constituents, Essential Oil and Antioxidant Activity of Marsh Woundwort (Stachys palustris L.)

Stachys palustris, well-known as marsh woundwort, is a perennial herb growing in wet environments of Europe. Its tubers, leaves and seeds are eaten raw or cooked. Alike other Stachys species, the plant is also used as a traditional remedy. Despite S. palustris has been consumed for centuries, little is known about its chemical constituents. In this work the main secondary metabolites of S. palustris from Hungary and France have been analysed. From the plant ethanolic extracts, ethanoid glucosides, isoscutellarein derivatives, caffeoyl-quinic acids and iridoids have been isolated and structurally characterized by NMR. The essential oils were analysed by GC/MS and showed (E)-phytol, fatty acids and carbonylic compounds as the most abundant compounds. The radical scavenging capacity of plant ethanolic extracts, as evaluated by the DPPH assay, was noteworthy, with IC₅₀ values of 92.08 - 105.42 μg/ml.

Constituents of Melittis melissophyllum subsp. albida

In this paper, for the first time, we have reported the analysis of the polar fraction of Melittis melissophyllum subsp. albida, a species with ecological relevance which is also used in traditional medicine of Central-Southern Italy. Iridoid glucosides were mainly identified, together with verbascoside, an ubiquitous phenyl-ethanoid glycoside, with chemotaxonomic implications in Lamiales order. The majority of the isolated compounds is endowed with interesting bio-activities and may justify the traditional uses of this plant also from a chemical point of view. Several peculiarities were also recorded in the metabolic pattern of this subspecies, i.e. the presence of virginioside and geniposidic acid, two rare compounds in the Lamiaceae family. The presence of free cinnamic acid was an additional characteristic of this subspecies which showed a specific secondary metabolites content. These phytochemical peculiarities, together with the morphological differences showed by the subsp. albida in respect to the nominal species, may be a base for a reconsideration of the systematic of Melittis melissophyllum subsp. albida.