J. of Chromatogr. Sci. 59 (7), 634-641 (2021). TLC of ledipasvir on silica gel with ethylacetate – hexane – acetonitrile – trimethylamine 12:7:3:1. Detection by exposure to strong UV irradiation to enhance the fluorescence properties of ledipasvir and densitometric scanning at 315 nm⁠. The hRF of ledipasvir was 28 and of sofosbuvir 36. Linearity was in the range of 5-50 ng/band⁠. The method is suitable for the specific determination of ledipasvir in pharmaceutical tablets without interference from sofosbuvir or excipients, thus for the estimation of ledipasvir in fecal specimens with adequate recovery and for testing the content uniformity of ledipasvir in the pharmaceutical tablets.

Planta Med. 85(3), 195-202 (2019). The dichloromethane fraction of an ethanolic extract from Gloeophyllum odoratum sporocarp (Gloeophyllaceae, Basidiomycetes) was submitted to a multistep purification process (conventional, flash and supercritical fluid column chromatography). At each step, fractions were monitored on TLC silica gel with dichloromethane – methanol – water 40:4:1. Detection under white and UV light after derivatization with vanillin sulfuric acid 5 % in methanol and heating. Eight triterpenes were isolated for further identification: eburicodiol, gloeophyllins B and K, hydroxylanosterol, trametenolic acid B (all five from the lanostane type), gloeophyllins A and L (C‑nor-D-homoergosteroid type), and ergosterol peroxide (ergostane type).

Planta Med. 85(2), 154-159 (2019). Two new cycloartane triterpene heterosides (cimiheraclein F and a shengmanol derivative) isolated from Actaea heracleifolia aerial parts (Ranunculaceae) were submitted to acid hydrolysis (HCl 0.4 M in methanol 60 %, 90°C, 2 h). The glycone moieties were purified and developed on TLC silica gel with ethyl acetate – chloroform – methanol – water 3:2:2:1. Detection after spraying with sulfuric acid 10 % in water and heating. The glycones were identified in both cases as L-arabinopyranose by comparison of the RF values (and of specific optical rotation) to a standard.

Planta Med. 85(2), 112-117 (2019). A fraction of an ethanolic extract of Dolichos trilobus roots (Fabaceae) was eluted on a silica gel column with different mixtures of petroleum ether and acetone. This fractionation was monitored by TLC on silica gel (eluent not given), derivatization by spraying with sulfuric acid 10 % (in ethanol) and heating (100 °C). Further isolation steps allowed the identification of eight coumestans in two subfractions: dolichosins A–D, isosojagol, phaseol, psoralidin, dehydroisopsoralidin.

Sci. World J. 2020, 7367836 (2020). TLC of ethyl acetate fractions of hydro ethanolic extracts obtained from Cassia siamea leaves (Caesalpiniaceae) on silica gel with chloroform – ethanol 17:3, as well as cassiarin A (an isoquinoline alkaloid, hRF 34) as standard. Visualization under UV light. Densitometry scanning at 368 nm for cassiarin A. Linearity was in the range of 400–1400 ng; intra-day precision was below 4 %; LOD and LOQ values were 3 and 8 ng, respectively; recovery rates were 102.8–120.1 %. The cassiarin A concentrations in the samples (given as w/v, the volumes being those of the first undried hydro-ethanolic extracts) varied depending on the origin (ground and climate) of the leaves.

Foods 9(8), 1136 (2020). TLC of methanolic decoctions and ultrasonication extracts from Zingiber officinale (Zingiberaceae) rhizomes, as well as from commercial ginger formulations, on reverse-phase C18-silica gel with ethanol – water 13:7. Densitometry at 200 nm in absorbance and reflectance modes for 6-shogaol (SHO, hRF 36) and 6-gingerol (GIN, hRF 53). Standards of these vanilloid phenolics were also used for calibration; linearity was in the range of 100–700 ng for SHO and of 50–600 ng/band for GIN; interday and intra-day precisions were below 1.6 %. The LOD and LOQ was 34 and 101 ng for SHO, 17 and 51 ng for GIN, respectively. Recovery rates were 98.8–101.6 % for SHO and 99.0–101.5 % for GIN. For each extract, SHO and GIN levels were calculated, the yields after ultrasonication extraction were 10-25 % higher than with the corresponding decoctions. Comparison with other published methods (LC-MS and HPLC) showed superiority of this new method in terms of linearity range, accuracy and precision.

3 Biotech 10(8), 344 (2020). Rauvolfia serpentina (Apocynaceae) was cultivated in vitro as leaf-derived callus and as plantlet cultures obtained from tissues of nodal explants, without or with cadmium chloride as elicitor of alkaloid production. TLC of methanol – ammonia 10:1 extracts of callus and plantlet organs (leaves, stems and roots) on silica gel, along with indole alkaloids reserpine and ajmalicine in different concentrations. Development with chloroform – toluene – ethyl acetate – diethyl amine 7:7:4:1. Detection under UV light and by densitometry scanning in absorbance mode at 240 nm and 280 nm. The highest alkaloid yields were obtained for reserpine (hRF 15) in roots (191µg/g) and for ajmalicine (hRF 45) in callus (131µg/ml) when culture had been done with elicitor 0.15 mM for 6 days and 4 days, respectively (at 0.20 mM, an inhibiting effect was observed).

Heliyon 6(8), e04654 (2020). HPTLC of ethanolic extracts of three algae (100µg/band) on silica gel, along with carotenoid standards (10µg/band), developed with toluene – acetone 7:3. Detection under white light. Carotenoids appeared orange or yellow, chlorophylls green, pheophytins dark khaki. Carotenoid patterns of the algae were very different depending on the family: red alga Eucheuma denticulatum (Solieriaceae) contained mainly zeaxanthin and lutein (hRF 44) and β-carotene (hRF 88), but also β-cryptoxanthin (hRF 69-71) and fucoxanthin (hRF 39); brown alga Sargassum polycystum (Sargassaceae) contained mainly fucoxanthin, and also cryptoxanthin; green alga Caulerpa lentillifera (Caulerpaceae) contained mainly zeaxanthin, but also astaxanthin (hRF 61) and canthaxanthin (hRF 77) in smaller amounts. Separately, HPLC-MS was used to confirm and quantify these compounds, which was necessary for carotenoids with similar hRF values: zeaxanthin and lutein (hRF 44), and β-carotene and lycopene (hRF 88).