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).

Planta Med. 84(18), 1348-1354 (2018). A subfraction (obtained through liquid-liquid partition and column chromatography) of the ethanolic extract of whole Vernonia cinerea plants (Asteraceae, subf. Cichorioideae) was further fractioned by reverse-phase SPE (solid-phase extraction) followed by preparative TLC on silica gel layer (eluent not given). For verification, zones were detected by spraying with anisaldehyde solution with 10 % sulfuric acid, followed by heating at 100 °C. Further purification by reverse-phase HPLC allowed the isolation of 6 hirsutinolide-type sesquiterpenoids (all with a oxacyclonane forming an ether bridge), including vernolides A and B.

Planta Med. 84(18), 1340-1347 (2018). Preparative TLC on silica gel for the final purification of 15 phenylethyl-chromenone derivatives (including 3 with epoxide functions), 4 sesquiterpenoids (neopetasane, dehydrokaranone, dioxoselinene, ligudicin C) and a steroid (ergostatetraenone), all isolated through multi-step column chromatography from the ethyl-acetate fraction of a methanolic extract of Aquilaria sinensis resinous wood (Thymelaeaceae). For each compound, mobile phase, RF value and yield are given.

J. Liq. Chromatogr. Relat. Technol. 43, 344-350 (2020). HPTLC of hydrodistilled Plectranthus amboinicus essential oil on silica gel with n-hexane - ethyl acetate - ethanol 95:3:2. Detection by dipping into anisaldehyde sulfuric acid reagent, followed by heating at 100 ºC for 5 min. HPTLC-bioprofiling was performed using the following assays by dipping the chromatogram into the respective solution, followed by drying, incubation and documentation at white light or measuring bioluminescence: DPPH* radical reagent assay (using a 0.2 mg/mL 2,2-diphenyl-1-picrylhydrazyl solution in methanol), AChE inhibitory assay, tyrosinase inhibitory assay, alpha- and beta-glucosidase inhibitory assays, alpha-amylase inhibitory assay, Gram-negative antimicrobial bioassay (chromatogram immersion into a A. fischeri suspension), and Gram-positive antimicrobial bioassay (chromatogram immersion into a B. subtilis bacterial suspension). Direct analysis in real time mass spectrometry allowed the detection of five bioactive compounds: caryophyllene oxide (hR_F 20), a-humulene (hR_F 26), carvacrol (hR_F 40), methyl carvacrol ether (hR_F 76) and caryophyllene (hR_F 84).

Planta Medica 84(9/10), 716-720 (2018). The fractionations of n-hexane and chloroform extracts of Guarea guidonia aerial parts (Meliaceae) through silica gel column chromatography was monitored on TLC silica gel with cerium sulfate / sulfuric acid as derivatization reagent. In the fractions obtained, 3 new tirucallane-type triterpenoids (guareolide, guareoic acids A and B) were further identified, as well as other terpenoids (flindissone, acetyldihydronomilin, picroquassin E, boscartol C, and acneorubins A, B, and X).

Planta Medica 84(9/10), 729-735 (2018). The chloroform fraction of a methanolic extract of Euphorbia taurinensis whole plant (Euphorbiaceae) was submitted to a multi-step fractionation through column chromatography. Monitoring by TLC on silica gel (mobile phases see below) followed by derivatization with concentrated sulfuric acid and heating at 105°C. The fractions obtained were purified by repeated cycles of preparative TLC alone or alternating with preparative HPLC, leading to the isolation of segetane, ingenane, and jatrophane diterpenes. Depending on the subfractions, preparative TLC silica gel and reverse-phase C18 layers were used, with cyclohexane – ethyl acetate – ethanol 25:15:1 for normal phase, and with mixtures of acetonitrile (or methanol) and water for RP.

Planta Medica 84(1), 59-64 (2018). A multi-step fractionation through silica gel column chromatography (CC) of a methanolic extract of Plectranthus africanus (whole plant, Lamiaceae) was monitored through TLC on silica gel with various solvent mixtures (n-hexane or dichloromethane with either acetone or methanol). Zones were detected under UV and further by spraying with sulfuric acid 20 % and heating at 100°C. For each fraction or TLC profile, the authors provide the CC gradient, the optimal proportions of the solvents used for the TLC mobile phase, as well as the RF values of the molecules isolated by this CC method: new abietane-type diterpenoids (plectranthroyleanones A, B, C), betulinic and oleanolic acids, heterosides of apigenin, rhamnetin and sitosterol.

J. Planar Chromatogr. 32, 359-364 (2019). HPTLC of Schizonepeta annua on silica gel with chloroform - toluene - acetic acid 600:100:3. Detection by spraying with 5 % vanillin - sulfuric acid reagent (mixture of 2.5 g vanillin, 45 mL ethanol, and 5 mL concentrated sulfuric acid), followed by heating at 105 °C for 5 min. Antibacterial assay was performed by dipping the plate into a cell suspension culture (Brain heart infusion broth and brain heart infusion agar in the ratio of 9:1), followed by incubation at 35 °C for 16 h and immersion into 0.2 % MTT solution for 3s, followed by incubation at 35 °C for 3h. Plates were scanned at 546 nm. The hRF values for thymol and carvacol were 88 and 78, respectively.