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Two new monoterpenoid indole alkaloids, gelselegandines F (<b>1</b>) and G (<b>2</b>), were isolated from the aerial parts of <i>Gelsemium elegans</i>. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. The ECD calculations were conducted at the B3LYP/6-311G(d,p) level and NMR calculations were carried out using the Gauge-Including Atomic Orbitals (GIAO) method. Structurally, the two new compounds possessed rare, cage-like, monoterpenoid indole skeletons. All isolated compounds and the total alkaloids extract were tested for cytotoxicity against four different tumor cell lines. The total alkaloids extract of <i>G. elegans</i> exhibited significant antitumor activity with IC₅₀ values ranging from 32.63 to 82.24 ug/mL. In order to discover anticancer leads from the active extraction, both new indole compounds (<b>1–2</b>) were then screened for cytotoxicity. Interestingly, compound <b>2</b> showed moderate cytotoxicity against K562 leukemia cells with an IC₅₀ value of 57.02 uM.