Chinese J. Pharm. Research 42 (2), 98-104 (2023). Ganoderma lucidum is the dry fruiting body of fungus, a medicinal plant, having the effect of relieving asthma and relieving nerves. Ganoderma lucidum is widely distributed in China and mainly concentrated in Zhejiang, Anhui, Shandong, Jilin, and Fujian. In this study, the HPTLC method for quality detection and origin traceability was established towards the medicinal material produced in Fujian and other areas. HPTLC of the ethanol extracts of the sample materials on silica gel with chloroform – acetonitrile – methanol – formic acid 130:15:2:2, three times to distances of 3 cm, 6 cm, 8 cm. Detection by spraying with 3 % sulfuric acid in ethyl acetate and heating at 105°C until the bands are clearly visualized, evaluation at UV 366 nm. The bands on the thin layer chromatogram were identified by fingerprint comparison using standard samples, and cluster analysis for the data of samples from different producing areas was performed using digital characterization. As results, the HPTLC analysis detected 17 distinct bands and among them, 11 components were identified, e.g. ganoderenic acid C (hRf 0.31), ganoderic acid C2 (hRf 33), ganoderic acid l (hRf 35), ganoderic acid G (hRf 41), ganoderic acid A (hRf 44), ganoderic acid B (hRf 46), ganolactone B (hRf 53), 3β,7β,15β-trihydroxy-11,15-dihydroxy-lanostane-8-alkene-24→20 lactone (hRf 56), ganoderenic acid D (hRf 61), ganoderic acid D (hRf 63) and 20 (21)-dehydrolucidenic acid A (hRf 65). A total of 10 HPTLC bands were identified in Fujian Ganoderma lucidum, among which ganoderic acid C2, ganoderic acid D and two unknown component bands (hRf 14 and 17) were unique and could be used as markers of Fujian Ganoderma lucidum. Thus samples of Fujian Ganoderma lucidum can be differentiated from those of other areas, when the Euclidean distance is 25 in Euclidean cluster analysis.

J Chromatogr Sci, 61 (3), 269-278 (2023). Development of a method for identification, quantification and stability study of linalool in Homalomena aromatica Schott, a herb with anti-rheumatism, nourishing and strengthening effects, and for the treatment of stomach disease. HPTLC hyphenated with MS for linalool on silica gel with toluene - ethyl acetate 19:1. Detection  with p-anisaldehyde reagent. The hRf of linalool is 35, identification of linalool at m/z 137, (M + H)+ by using MS technique. Study of the stability of linalool by investigating the effect of acid, base, UV, sunlight, thermal stress and H2O2 on it, the highest effect was observed with acidic pH with a 65 % degradation. The content of linalool was 58 % in the volatile oil of H. aromatica.

J  Chromatogr Sci, 61(3), 225-233 (2023). Development of a method for analyzing rosmarinic acid (RA), caffeic acid (CA), ursolic acid (UA) and oleanolic acid (OA) in different organs of Salvia deserta Schang qualitatively and quantitatively by HPTLC (A) for RA and CA, on silica gel with chloroform – methanol - formic acid 20:4:1, quantitative absorption measurement at 330 nm; (B) for UA and OA, on silica gel F254 with cyclohexane - ethyl acetate - methanol 20:4:1, quantitative absorption measurement at 550 nm. The linearity ranges were 0.13-0.44, 0.01-0.09, 0.50-2.50 and 0.50-2.50 mg for RA, CA, UA and OA, respectively, with corresponding correlation coefficients of 0.9938, 0.9981, 0.9971 and 0.9969, respectively. The recovery rates were between 95 % and 105 %. LOD and LOQ were 50, 58, 25, 33 and 160, 191, 80, 106 ng for RA, CA, UA and OA, respectively.

J Chromatogr Sci, 61 (1), 66-73 (2023). Development of a rapid, easy and simple method for the isolation and purification of α-glucosidase inhibitors of the ethyl acetate extract of Thymelaea hirsuta (EaTh) by TLC-enzymatic test (TLC/EZ), after EaTh demonstrated previously a potent α-glucosidase inhibitory effect. Soxhlet extraction from Thymelaea hirsuta (T. hirsuta), separation on a silica gel column, TLC on silica gel. Detection of α-glucosidase inhibitors directly on the TLC plate using the glucose oxidase peroxidase method (GOD-POD), then characterization of active compounds using HPLC-MS analysis, resulting the main α-glucosidase inhibitors present in EaTh with a molecular ion [M + H]+ at m/z = 543. The proposed method is suitable for a reliable isolation and purification of α-glucosidase inhibitors present in EaTh and can be proposed as an interesting alternative to the classical method for the isolation and purification of α-glucosidase inhibitors in plant extracts.

J. Chinese Trad. Patent Med. 44 (6), 1770-1772 (2022). Ganqingqinglan (Dracocephalum tanguticum Maxim.) is a traditional Tibetan medicinal plant, containing flavonoids, terpenes, polysaccharides. It has antihypoxic, antibacterial, antiviral, and hypoglycemic effects and is used as the main component in the traditional Tibetan medicine for the treatment of hepatitis and gastritis. For quality control, TLC of the plant extracts on silica gel (1) for oleanic acid, with toluene - ethyl acetate - glacial acetic acid 28:8:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C until the zones are clearly visualized, evaluation under UV 366 nm; (2) for chlorogenic acid, with toluene - methyl acetate - propanone - methanol - methyl acid 30:5:5:20:1, evaluation under UV 366 nm. The method was applied for the analysis of 18 batches of real life samples and proved to be simple, specific, reproducible, robust and well suitable for the purpose.

J Pharmacogn Phytochem, 12(1), 159-167 (2023). TLC of methanolic Soxhlet extracts on silica gel with toluene – ethyl acetate – formic acid 16:4:1. Visualization under UV 254 nm and 366 nm. Two bands only (hRF values 10 and 45), observed with densitometric scanning at UV 366 nm, were present in Trianthema portulacastrum roots (Aizoaceae), whereas a different profile was observed with Boerhavia diffusa roots (Nyctaginaceae), which is sometimes substituted for T. portulacastrum.

J Pharm Bioallied Sci 15(Suppl.2), S948-S951 (2023). Sample was the ethyl acetate fraction of an ethanolic extract of Viola odorata aerial parts (Violaceae). Standards were coumarinic compounds: esculetin (1) and umbelliferone (2). TLC and HPTLC on silica gel with toluene – ethyl acetate – formic acid 5:4:1. Visualization under UV 254 nm and 366 nm; densitometric scanning at 366 nm. Both (1) and (2) were found in the extract (hRF values 30 and 53, respectively, in TLC). Alternative mobile phases were also tested (TLC only): toluene – ethyl acetate 1:1 (hRF values 47 and 68) and chloroform – methanol 97:3 (hRF values 20 and 41).

 J. Pharmacogn. Phytochem. 12(1), 6-14 (2023). TLC silica gel layers were used to monitor the purification through column chromatography (CC) of a chloroform fraction of the methanolic root bark extract of Rauvolfia vomitoria (Apocynaceae). Mobile phases were petroleum ether – ethyl acetate 4:1 (MP1), dichloromethane – methanol 20:1 (MP2), and dichloromethane – methanol 15:1 (MP3). Visualization under UV 254 nm. Preparative TLC on thicker silica gel was performed on two subfractions: (A) with dichloromethane – methanol 100:7 for the isolation of the methyl esters of eudesmic acid and of trimethoxycinnamic acid (hRF values 35 and 28, respectively, in MP1); (B) with MP2 for the isolation of an indole alkaloid: kumujan B (= 1-carbomethoxy-β-carboline, hRF value 40 in MP2). Other indole alkaloids were isolated through CC: ajmaline, mauensine and reserpine (hRF values 35, 13 and 47, respectively, in MP3).