Trichosanthes cordata

Trichosanthes cordata Roxb., Fl. Ind., ed. 1832 3: 703–704 1832. (syn: Anguina cordata (Roxb.) Kuntze; Involucraria cordata (Roxb.) M. Roem.; Trichosanthes microsiphon Kurz; Trichosanthes tuberosa Roxb. ex Wight & Arn. (ambiguous synonym));  

SE-Tibet, India, peninsular Malaysia, Myanmar [Burma] (Bago), Darjeeling, Nepal, Bangladesh as per Catalogue of Life;

Climber; root tuberous; stem robust, angular, ribbed, glabrous or sparsely puberulent. Leaves simple, alternate, spiral; petioles ca. 3-6 cm long; lamina ca. 7-18 x 7-10 cm, broadly cordate-ovate, cordate at base, acuminate at apex, margin dentate-serrate, chartaceous; secondary nerves 3-5 pairs; tendrils 2-3-fid, robust, sulcate, puberulous. Flowers ca. 3.5-4 cm across, yellow; Male flowers ca. 10-20 cm long, 2-4-flowered racemes; bracts obovate, hairy; calyx tube ca. 3.5 cm long; Female flowers subsessile, solitary. Fruits ca. 4-4.5 cm in diam., white banded, globose, shiny red. Seeds ca. 1.2 x 0.5 cm, subquadrangular.
In secondary forests, on bushes; 400-600 m.
Bhutan, India (West Bengal, Sikkim, Assam, Meghalaya, Tripura, Arunachal Pradesh), Laos, Malaysia, Myanmar, Nepal, Singapore
(Attributions- French Institute of Pondicherry from India Biodiversity Portal)
SK774 06 OCT-2017:ID : 8 posts by 2 authors. Attachments (8)
Location :  Way to Pokhara, Nepal 
Date : 14 August 2017
Altitude : 2200 ft.
Cucurbitaceae ... ??

Very interesting. Pl. check comparative images at family page. 

I did.

Also I could not find any match at Cucurbitaceae  

Trichosanthes spp ...???

There appears to be some possibility for Trichosanthes sp. going by bracts at Trichosanthes tricuspidata Lour.  
However could not find a match as per comparative images available at Trichosanthes and as per images below (based on Checklist of Nepal):

Yes, it is a Trichosanthes, but I would need to see a dried specimen to decide on the species.
It is very easy to dried a few leaves and flowers between newspaper and send them to me for identification. There is nothing that prohibits the exchange of material among international herbaria. I just wished my Indian colleagues would understand that. The only thing that will document (and thereby protect) the Indian flora for the future is specimens in herbaria, not photos. 
Thank you for your concern. Unfortuntely I did not collect the specimen and it is very far from my place. May be I would collect next time when I pass through the area. By the way it is from Nepal.

Does any of the images shows matching bracts? 

Looks different.