High-performance thin-layer chromatographic methods in the evaluation of the antioxidant and anti-hyperglycemic activity of Myrmecodia platytyrea as a promising opportunity in diabetes treatment

Evaluation of bioactive compounds from Ficus carica L. leaf extracts via high-performance thin-layer chromatography combined with effect-directed analysis

This study compares different solvent systems with the use of spontaneous fermentation on the phytochemical composition of leaf extracts from a locally grown white variety of common fig (Ficus carica Linn.). The aim was to detect and identify bioactive compounds that are responsible for acetylcholinesterase (AChE), α-amylase and cyclooxygenase-1 (COX-1) enzyme inhibition, and compounds that exhibit antimicrobial activity. Bioactive zones in chromatograms were detected by combining High-performance thin-layer chromatography (HPTLC) with enzymatic and biological assays. A new experimental protocol for measuring the relative half-maximum inhibitory concentration (IC50) was designed to evaluate the potency of the extracts compared to the potency of known inhibitors. Although the IC50 of the fig leaf extract for α-amylase and AChE inhibition were significantly higher when compared to IC50 for acarbose and donepezil, the COX-1 inhibition by the extract (IC50 = 627 µg) was comparable to that of salicylic acid (IC50 = 557 µg), and antimicrobial activity of the extract (IC50 = 375-511 µg) was similar to ampicillin (IC50 = 495 µg). Four chromatographic zones exhibited bioactivity. Compounds from detected bioactive bands were provisionally identified by comparing the band positions to coeluted standards, and by Fourier transform infrared (FTIR) spectra from eluted zones. Flash chromatography was used to separate selected extract into fractions and isolate fractions that are rich in bioactive compounds for further characterisation with nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) analysis. The main constituents identified were umbelliferon (zone 1), furocoumarins psoralen and bergapten (zone 2), different fatty acids (zone 3 and 4), and pentacyclic triterpenoids (calotropenyl acetate or lupeol) and stigmasterol (zone 4).

Effect directed analysis of bioactive compounds in leaf extracts from two Salvia species by High-performance thin-layer chromatography

Extracts of two Salvia species, Salvia apiana (white sage) and Salvia officinalis (common sage) were screened for phytoconstituents with the ability to act as antidiabetic, cognitive enhancing, or antimicrobial agents, by hyphenation of high-performance thin-layer chromatography with enzymatic and microbial effect directed assays. Two bioactive zones with α-amylase inhibition (zone 1 and zone 2), 3 zones for acetylcholinesterase inhibition (zones 3, 4 and 5), and two zones for antimicrobial activity (zones 4 and 5) were detected. The compounds from the five bioactive zones were initially identified by coelution with standards and comparing the R_F values of standards to the bioautograms. Identity was confirmed with ATR-FTIR spectra of the isolated compounds from the bioactive zones. A significantly higher α-amylase and acetylcholinesterase inhibition of S. apiana leaf extract was associated with a higher flavonoid and diterpenoid content. Fermented S. officinalis extract exhibited a significantly higher ability to inhibit α-amylase compared to other non-fermented extracts from this species, due to increased extraction of flavonoids. The ATR-FTIR spectra of 2 zones with α-amylase inhibition, indicated that flavonoids and phenolic acids were responsible for α-amylase inhibition. Multiple zones of acetylcholinesterase inhibition were related to the presence of phenolic abietane diterpenoids and triterpenoid acids. The presence of abietane diterpenoids and triterpenoid acids was also found responsible for the mild antimicrobial activity. Flash chromatography was used to isolate sufficient amounts of bioactive compounds for further characterisation via NMR and MS spectroscopy. Five compounds were assigned to the zones where bioactivity was observed: cirsimaritin (zone 1), a caffeic acid polymer (zone 2), 16-hydroxyrosmanol (zone 3), 16-hydroxycarnosic acid (zone 4), oleanolic and ursolic acids (zone 5).

Medicinal Properties of Ant Nest Plant (Myrmecodia Genus): A Comprehensive Review

BACKGROUND: The Myrmecodia genus belongs to the Rubiaceae family, which has the characteristic of an epiphytic plant. This genus spread from Malaysia, through the Philippines, Sumatra, Borneo, Java, New Guinea (Papua), Cape York to the Solomon Islands and Pacific region. It has been empirically proven to treat gout, inflammation, muscle pain relief, strengthen the body’s immunity, and cancer treatment. AIM: This article reviewed the scientific work about the Myrmecodia genus concerning their traditional uses, phytochemical compounds, and pharmacological activities of Myrmecodia. METHODS: The sources were from the scientific literature online database, including Science Direct, PubMed, and Google Scholar between 1978 and 2021. Furthermore, 112 articles were collected, while 61 full-text were assessed for eligibility. RESULTS: The Myrmecodia extract has many pharmacological activities, namely antioxidant, antibacterial, cytotoxic, and anticancer. CONCLUSION: Moreover, this review may be used as scientific literature for the next investigations on the genus Myrmecodia, especially regarding pharmacological properties such as in vitro and in vivo studies and isolation of the active compounds.

The effect of extractive lacto-fermentation on the bioactivity and natural products content of Pittosporum angustifolium (gumbi gumbi) extracts

Pittosporum angustifolium, known as gumbi gumbi, is a native Australian plant, which has traditionally been used as an Aboriginal medicine. This study investigates the effect of different solvents and extractive fermentation on the content and natural products composition of Pittosporum angustifolium extracts, and compares their antioxidant activity, in vitro α-amylase inhibition, and anti-inflammatory properties. Anti-inflammatory activity of the extracts was determined by measuring the inhibition of nitric oxide (NO) production. Extracts were characterised with FTIR-ATR spectroscopy, and screened for antioxidant activities and α-amylase inhibitory activity via High-performance thin-layer chromatography (HPTLC)-Effect-directed analysis (EDA) with direct bioautography. HPTLC combined with chemical derivatization and bioassays was used for EDA screening. The results show that lactic acid fermentation of gumbi gumbi leaves boosts the antioxidant activity in extracts by increasing the total phenolic content, but does not affect (increase or decrease) α-amylase inhibitory activity or nitrogen scavenging/anti-inflammatory activity. Analysis of the ATR-FTIR spectra from the band at R_F = 0.85 that inhibits α-amylase, suggests that fatty acid esters are responsible for the enzyme inhibition; both saturated fatty acid esters in unfermented extracts and unsaturated fatty acid esters in fermented extracts. The ATR-FTIR spectra of the polyphenolics in fermented extracts (R_F = 0.15-0.20) suggests the presence of soluble lignin fragments (i.e. lignins depolymerized into monomers and oligomers during the fermentation process).

Bioassay-guided identification of α-amylase inhibitors in herbal extracts

This study focuses on the health benefits of several fresh herbs that are commonly used in the Mediterranean diet. Antioxidant activity, phytosterol content and α-amylase inhibitory activity of fresh basil, lavender, oregano, rosemary, sage, and thyme are analyzed and compared. High-performance thin-layer chromatography (HPTLC) combined with effect directed analysis was used to detect and quantify biological active compounds on chromatograms. The highest antioxidant activity was measured in the extract from oregano leaf, while the highest terpenoid content was in basil leaf extract. All extracts except lavender leaf and lavender flower extracts showed α-amylase inhibition. The same compound at hR_F = 68 in basil, oregano, rosemary, sage, and thyme extracts was responsible for α-amylase inhibition. Combined with effect-directed assays and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, hyphenated HPTLC allowed a fast characterization of the active compound. ATR spectral analysis of this band tentatively identified oleanolic acid (or its derivative) to be responsible for the α-amylase inhibition.

HPTLC - Bioautographic methods for selective detection of the antioxidant and α-amylase inhibitory activity in plant extracts

A high-performance thin-layer chromatography (HPTLC) method was developed for quantification of α-amylase inhibitory activity and stigmasterol content in ant plant extracts. An improved HPTLC method for the determination of total free radical scavenging activity in samples using DPPH• is also reported. For quantification of α-amylase inhibitory activity, the developed HPTLC plate is dipped into an α-amylase solution, and the bioautogram is then incubated at 25 °C for 30 min under humid conditions. For visualization of enzyme inhibitory activity, the starch test with an iodine indicator solution is used. The blue zone observed comes from the starch-iodine complex formed from starch that was not hydrolyzed by the amylase due to enzyme inhibition by the compound(s) present in the sample. The area of the blue zones was used to compare and quantify relative α-amylase inhibitory activity in different extracts. Location of the blue zones (hRF) on the plate was used to detect compounds that are responsible for the α-amylase inhibitory activity. Relative α-amylase activity was not related to the antioxidant activity, but was highly correlated with the stigmasterol content in the sample extracts (R = 0.95). Therefore, plant sterols present in the extracts might be responsible for α-amylase inhibitory activities in the extracts.

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The developed method for quantification of α-amylase inhibitory activity provides an efficient and effective tool that can be used to screen, detect and quantify α-amylase inhibitory activity in plant extracts.

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The proposed protocol is easy to run, involves minimal sample preparation, with multiple samples able to be analyzed in parallel on the same chromatographic plate, in a short time.

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There were significant differences in α-amylase inhibitory activity, stigmasterol content, and total free radical scavenging activity between methanol, ethanol, dichloromethane, and ethyl acetate ant plant extracts.